Basis of Presentation (Details Textual) (USD $) In Millions, unless otherwise specified	6 Months Ended			12 Months Ended			6 Months Ended	12 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Revolving Credit Facility [Member]	Jan. 27, 2006 Revolving Credit Facility [Member]	Dec. 31, 2011 New Accounting Pronouncement, Early Adoption, Effect [Member]	Dec. 31, 2005 Hallmark Statutory Trust I [Member]	Dec. 31, 2007 Hallmark Statutory Trust I I [Member]	Jun. 30, 2012 Subordinated Debt [Member]	Dec. 31, 2005 Subordinated Debt [Member] Hallmark Statutory Trust I [Member]	Dec. 31, 2007 Subordinated Debt [Member] Hallmark Statutory Trust I I [Member]
Line of Credit Facility, Amount Outstanding		$ 1.6	$ 15.0
Trust Preferred Securities Fair Value							48.2
Trust Preferred Securities Carrying Value							56.7
Current Yield To Maturity Percentage	9.40%						8.00%
Proceeds from Issuance of Trust Preferred Securities					30.0	25.0
Payments to Acquire Trust Preferred Investments								30.9	25.8
Deferred Policy Acquisition Costs, Period Increase (Decrease)				(0.9)
Increase (Decrease) in Deferred Income Taxes				(0.3)
Stockholders' Equity, Period Increase (Decrease)				$ (0.6)