Regulatory Capital Restrictions (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Regulatory Capital Restrictions [Line Items]
Retained earnings, unappropriated	$ 35.5
Hallmark (Payee) [Member]
Regulatory Capital Restrictions [Line Items]
Dividends paid by subsidiaries	$ 15.5	$ 5.5
Hallmark (Payee) [Member] | Scenario, Forecast [Member]
Regulatory Capital Restrictions [Line Items]
Aggregate amount of shareholder dividends, maximum available next current fiscal year			$ 15.8
Subsidiaries [Member] | Scenario, Forecast [Member]
Regulatory Capital Restrictions [Line Items]
Aggregate amount of shareholder dividends, maximum available next current fiscal year			$ 22.6
American Hallmark Insurance Company and Texas Builders Insurance Company [Member]
Regulatory Capital Restrictions [Line Items]
Statutory Accounting Practices, Future Dividend Payments Restrictions	greater of statutory net income for the prior calendar year or 10% of statutory policyholders' surplus as of the prior year end
Hallmark Insurance Company And Hallmark National Insurance Company [Member]
Regulatory Capital Restrictions [Line Items]
Statutory Accounting Practices, Future Dividend Payments Restrictions	lesser of 10% of prior year policyholders' surplus or prior year's net income
Hallmark Specialty Insurance Company [Member]
Regulatory Capital Restrictions [Line Items]
Statutory Accounting Practices, Future Dividend Payments Restrictions	greater of 10% of prior year policyholders' surplus or prior year's statutory net income, not including realized capital gains
Hallmark Insurance Company Subsidiaries [Member]
Regulatory Capital Restrictions [Line Items]
Amount of restricted net assets for consolidated and unconsolidated subsidiaries	$ 227.8
Statutory accounting practices, statutory capital and surplus, balance	254.7	247.0
Statutory accounting practices, statutory net income amount	$ (10.2)	$ 35.9