Quarterly Financial Information (Unaudited) (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
Revenues	$ 63,461	$ 57,230	$ 56,502	$ 53,032	$ 56,866	$ 53,616	$ 53,608	$ 49,546	$ 230,225	$ 213,636	$ 202,759
Benefits and expenses	72,716	53,954	54,994	51,341	55,456	50,998	51,813	48,438	233,005	206,705	196,723
Federal income tax expense	1,921	952	358	494	604	794	488	252	3,725	2,138	1,507
Net income (loss)	(11,176)	2,324	1,150	1,197	806	1,824	1,307	856	(6,505)	4,793	4,529
Common Class A [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (11,176)	$ 2,324	$ 1,150	$ 1,197	$ 806	$ 1,824	$ 1,307	$ 856
Basic earnings per share	$ (0.22)	$ 0.04	$ 0.03	$ 0.02	$ 0.02	$ 0.03	$ 0.03	$ 0.02
Diluted earnings per share	$ (0.22)	$ 0.04	$ 0.03	$ 0.02	$ 0.02	$ 0.03	$ 0.03	$ 0.02
Common Class B [Member]
Basic earnings per share	$ (0.12)	$ 0.03	$ 0.01	$ 0.01	$ 0.01	$ 0.02	$ 0.01	$ 0.01
Diluted earnings per share	$ (0.12)	$ 0.03	$ 0.01	$ 0.01	$ 0.01	$ 0.02	$ 0.01	$ 0.01