Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Numerator for both basic and diluted earnings per share:
Net income (loss) attributable to Hallmark Financial Services, Inc.	$ 1,783	$ 3,413	$ (1,843)	$ 171	$ 311	$ 98	$ (87)	$ (11,213)	$ 3,524	$ (10,891)	$ 7,403
Denominator, basic shares									19,263	19,673	20,123
Effect of dilutive securities:
Stock options									6	0	52
Denominator, diluted shares									19,269	19,673	20,175
Basic earnings per share: (in dollars per share)	$ 0.09	$ 0.18	$ (0.10)	$ 0.01	$ 0.02	$ 0.01	$ 0.00	$ (0.56)	$ 0.18	$ (0.55)	$ 0.37
Diluted earnings per share: (in dollars per share)	$ 0.09	$ 0.18	$ (0.10)	$ 0.01	$ 0.02	$ 0.01	$ 0.00	$ (0.56)	$ 0.18	$ (0.55)	$ 0.37