diff --git a/internal/resource_org_setting/org_setting_resource_gen.go b/internal/resource_org_setting/org_setting_resource_gen.go
index 06b15a0..ca0a4d4 100644
--- a/internal/resource_org_setting/org_setting_resource_gen.go
+++ b/internal/resource_org_setting/org_setting_resource_gen.go
@@ -11,6 +11,7 @@ import (
 	"github.com/hashicorp/terraform-plugin-framework-validators/stringvalidator"
 	"github.com/hashicorp/terraform-plugin-framework/attr"
 	"github.com/hashicorp/terraform-plugin-framework/diag"
+	"github.com/hashicorp/terraform-plugin-framework/path"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/booldefault"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/int64default"
 	"github.com/hashicorp/terraform-plugin-framework/resource/schema/stringdefault"
@@ -402,6 +403,7 @@ func OrgSettingResourceSchema(ctx context.Context) schema.Schema {
 						Computed: true,
 						Validators: []validator.List{
 							listvalidator.SizeAtLeast(1),
+							mistvalidator.RequiredWhenValueIsNotNull(path.MatchRelative().AtParent().AtName("default_idp_id")),
 						},
 					},
 					"server_cert": schema.SingleNestedAttribute{
diff --git a/internal/validators/required_when_value_is_not_null.go b/internal/validators/required_when_value_is_not_null.go
new file mode 100644
index 0000000..cff820c
--- /dev/null
+++ b/internal/validators/required_when_value_is_not_null.go
@@ -0,0 +1,225 @@
+package mistvalidator
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/hashicorp/terraform-plugin-framework/attr"
+	"github.com/hashicorp/terraform-plugin-framework/diag"
+	"github.com/hashicorp/terraform-plugin-framework/path"
+	"github.com/hashicorp/terraform-plugin-framework/schema/validator"
+	"github.com/hashicorp/terraform-plugin-framework/tfsdk"
+)
+
+var (
+	_ NineTypesValidator = RequiredWhenValueIsNotNullValidator{}
+)
+
+type RequiredWhenValueIsNotNullValidator struct {
+	expression path.Expression
+}
+
+type RequiredWhenValueIsNotNullRequest struct {
+	Config         tfsdk.Config
+	ConfigValue    attr.Value
+	Path           path.Path
+	PathExpression path.Expression
+}
+
+type RequiredWhenValueIsNotNullResponse struct {
+	Diagnostics diag.Diagnostics
+}
+
+func (o RequiredWhenValueIsNotNullValidator) Description(_ context.Context) string {
+	return fmt.Sprintf("Ensures that a value is supplied when attribute %q is not defined", o.expression.String())
+}
+
+func (o RequiredWhenValueIsNotNullValidator) MarkdownDescription(ctx context.Context) string {
+	return o.Description(ctx)
+}
+
+func (o RequiredWhenValueIsNotNullValidator) Validate(ctx context.Context, req RequiredWhenValueIsNotNullRequest, resp *RequiredWhenValueIsNotNullResponse) {
+	// can't proceed while value is unknown
+	if req.ConfigValue.IsUnknown() {
+		return
+	}
+
+	// if we have a value there's no need for further investigation
+	if !req.ConfigValue.IsNull() {
+		return
+	}
+
+	mergedExpressions := req.PathExpression.MergeExpressions(o.expression)
+
+	for _, expression := range mergedExpressions {
+		matchedPaths, diags := req.Config.PathMatches(ctx, expression)
+		resp.Diagnostics.Append(diags...)
+		if resp.Diagnostics.HasError() {
+			return
+		}
+
+		for _, mp := range matchedPaths {
+			// If the user specifies the same attribute this mist_validator is applied to,
+			// also as part of the input, skip it
+			if mp.Equal(req.Path) {
+				continue
+			}
+
+			var mpVal attr.Value
+			resp.Diagnostics.Append(req.Config.GetAttribute(ctx, mp, &mpVal)...)
+			if resp.Diagnostics.HasError() {
+				continue // Collect all errors
+			}
+
+			// Unknown and Null attributes can't satisfy the valueIs condition
+			if !mpVal.IsNull() {
+				resp.Diagnostics.AddAttributeError(
+					req.Path,
+					"Missing required attribute",
+					fmt.Sprintf("Attribute %s required when %s is defined.", req.Path, mp.String()),
+				)
+			}
+		}
+	}
+}
+
+func (o RequiredWhenValueIsNotNullValidator) ValidateBool(ctx context.Context, req validator.BoolRequest, resp *validator.BoolResponse) {
+	validateReq := RequiredWhenValueIsNotNullRequest{
+		Config:         req.Config,
+		ConfigValue:    req.ConfigValue,
+		Path:           req.Path,
+		PathExpression: req.PathExpression,
+	}
+
+	validateResp := &RequiredWhenValueIsNotNullResponse{}
+
+	o.Validate(ctx, validateReq, validateResp)
+
+	resp.Diagnostics.Append(validateResp.Diagnostics...)
+}
+
+func (o RequiredWhenValueIsNotNullValidator) ValidateFloat64(ctx context.Context, req validator.Float64Request, resp *validator.Float64Response) {
+	validateReq := RequiredWhenValueIsNotNullRequest{
+		Config:         req.Config,
+		ConfigValue:    req.ConfigValue,
+		Path:           req.Path,
+		PathExpression: req.PathExpression,
+	}
+
+	validateResp := &RequiredWhenValueIsNotNullResponse{}
+
+	o.Validate(ctx, validateReq, validateResp)
+
+	resp.Diagnostics.Append(validateResp.Diagnostics...)
+}
+
+func (o RequiredWhenValueIsNotNullValidator) ValidateInt64(ctx context.Context, req validator.Int64Request, resp *validator.Int64Response) {
+	validateReq := RequiredWhenValueIsNotNullRequest{
+		Config:         req.Config,
+		ConfigValue:    req.ConfigValue,
+		Path:           req.Path,
+		PathExpression: req.PathExpression,
+	}
+
+	validateResp := &RequiredWhenValueIsNotNullResponse{}
+
+	o.Validate(ctx, validateReq, validateResp)
+
+	resp.Diagnostics.Append(validateResp.Diagnostics...)
+}
+
+func (o RequiredWhenValueIsNotNullValidator) ValidateList(ctx context.Context, req validator.ListRequest, resp *validator.ListResponse) {
+	validateReq := RequiredWhenValueIsNotNullRequest{
+		Config:         req.Config,
+		ConfigValue:    req.ConfigValue,
+		Path:           req.Path,
+		PathExpression: req.PathExpression,
+	}
+
+	validateResp := &RequiredWhenValueIsNotNullResponse{}
+
+	o.Validate(ctx, validateReq, validateResp)
+
+	resp.Diagnostics.Append(validateResp.Diagnostics...)
+}
+
+func (o RequiredWhenValueIsNotNullValidator) ValidateMap(ctx context.Context, req validator.MapRequest, resp *validator.MapResponse) {
+	validateReq := RequiredWhenValueIsNotNullRequest{
+		Config:         req.Config,
+		ConfigValue:    req.ConfigValue,
+		Path:           req.Path,
+		PathExpression: req.PathExpression,
+	}
+
+	validateResp := &RequiredWhenValueIsNotNullResponse{}
+
+	o.Validate(ctx, validateReq, validateResp)
+
+	resp.Diagnostics.Append(validateResp.Diagnostics...)
+}
+
+func (o RequiredWhenValueIsNotNullValidator) ValidateNumber(ctx context.Context, req validator.NumberRequest, resp *validator.NumberResponse) {
+	validateReq := RequiredWhenValueIsNotNullRequest{
+		Config:         req.Config,
+		ConfigValue:    req.ConfigValue,
+		Path:           req.Path,
+		PathExpression: req.PathExpression,
+	}
+
+	validateResp := &RequiredWhenValueIsNotNullResponse{}
+
+	o.Validate(ctx, validateReq, validateResp)
+
+	resp.Diagnostics.Append(validateResp.Diagnostics...)
+}
+
+func (o RequiredWhenValueIsNotNullValidator) ValidateObject(ctx context.Context, req validator.ObjectRequest, resp *validator.ObjectResponse) {
+	validateReq := RequiredWhenValueIsNotNullRequest{
+		Config:         req.Config,
+		ConfigValue:    req.ConfigValue,
+		Path:           req.Path,
+		PathExpression: req.PathExpression,
+	}
+
+	validateResp := &RequiredWhenValueIsNotNullResponse{}
+
+	o.Validate(ctx, validateReq, validateResp)
+
+	resp.Diagnostics.Append(validateResp.Diagnostics...)
+}
+
+func (o RequiredWhenValueIsNotNullValidator) ValidateSet(ctx context.Context, req validator.SetRequest, resp *validator.SetResponse) {
+	validateReq := RequiredWhenValueIsNotNullRequest{
+		Config:         req.Config,
+		ConfigValue:    req.ConfigValue,
+		Path:           req.Path,
+		PathExpression: req.PathExpression,
+	}
+
+	validateResp := &RequiredWhenValueIsNotNullResponse{}
+
+	o.Validate(ctx, validateReq, validateResp)
+
+	resp.Diagnostics.Append(validateResp.Diagnostics...)
+}
+
+func (o RequiredWhenValueIsNotNullValidator) ValidateString(ctx context.Context, req validator.StringRequest, resp *validator.StringResponse) {
+	validateReq := RequiredWhenValueIsNotNullRequest{
+		Config:         req.Config,
+		ConfigValue:    req.ConfigValue,
+		Path:           req.Path,
+		PathExpression: req.PathExpression,
+	}
+
+	validateResp := &RequiredWhenValueIsNotNullResponse{}
+
+	o.Validate(ctx, validateReq, validateResp)
+
+	resp.Diagnostics.Append(validateResp.Diagnostics...)
+}
+
+func RequiredWhenValueIsNotNull(expression path.Expression) RequiredWhenValueIsNotNullValidator {
+	return RequiredWhenValueIsNotNullValidator{
+		expression: expression,
+	}
+}