Unaudited Selected Quarterly Financial Information (Schedule of Quarterly Financial Information) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Unaudited Selected Quarterly Financial Information [Abstract]
Total revenue	$ 88,004	$ 81,417	$ 80,836	$ 87,109	$ 88,375	$ 108,613	$ 99,299	$ 93,141	$ 337,366	$ 389,428	$ 341,800
Total expense	82,404	76,689	78,794	80,697	83,613	99,141	104,616	90,978	318,584	378,348	338,426
Income (loss) before tax	5,600	4,728	2,042	6,412	4,762	9,472	(5,317)	2,163	18,782	11,080	3,374
Income tax expense (benefit)	1,833	1,265	391	1,864	1,334	3,198	(2,166)	469	5,353	2,835	(474)
Net income (loss)	3,767	3,463	1,651	4,548	3,428	6,274	(3,151)	1,694	13,429	8,245	3,848
Net income attributable to non-controlling interest											324
Net income (loss) attributable to Hallmark Financial Services, Inc.									$ 13,429	$ 8,245	$ 3,524
Basic earnings (loss) per share:	$ 0.20	$ 0.18	$ 0.09	$ 0.24	$ 0.18	$ 0.33	$ (0.16)	$ 0.09	$ 0.70	$ 0.43	$ 0.18
Diluted earnings (loss) per share:	$ 0.19	$ 0.18	$ 0.09	$ 0.23	$ 0.18	$ 0.32	$ (0.16)	$ 0.09	$ 0.69	$ 0.43	$ 0.18