Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements of Operations [Abstract]
Gross premiums written	$ 604,156	$ 549,077	$ 514,223
Ceded premiums written	(238,573)	(187,248)	(157,279)
Net premiums written	365,583	361,829	356,944
Change in unearned premiums	(4,546)	(8,459)	(7,863)
Net premiums earned	361,037	353,370	349,081
Investment income (loss), net of expenses	18,874	16,342	13,969
Other than temporary impairments	(5,877)	(2,888)	(3,323)
Net realized gains	5,672	2,519	5,826
Finance charges	3,867	4,977	5,952
Commissions and fees	1,679	1,427	213
Other income	269	205	684
Total revenues	385,521	375,952	372,402
Losses and loss adjustment expenses	288,308	253,688	230,149
Operating expenses	106,805	106,769	103,993
Interest expense	4,512	4,549	3,906
Amortization of intangible assets	2,468	2,468	2,468
Total expenses	402,093	367,474	340,516
Income (loss) before equity in undistributed earnings (loss) of subsidiaries and income tax benefit	(16,572)	8,478	31,886
Income tax expense (benefit)	(5,019)	1,952	10,023
Net income (loss)	(11,553)	6,526	21,863
Net income (loss) attributable to Hallmark Financial Services, Inc.	$ (11,553)	$ 6,526	$ 21,863
Net income (loss) per share attributable to Hallmark Financial Services, Inc. common stockholders:
Basic (in dollars per share)	$ (0.63)	$ 0.35	$ 1.14
Diluted (in dollars per share)	$ (0.63)	$ 0.34	$ 1.13