Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues	$ 62,205	$ 58,124	$ 60,079	$ 55,860	$ 63,461	$ 57,230	$ 56,502	$ 53,032	$ 236,268	$ 230,225	$ 213,636
Benefits and expenses	64,185	58,263	60,917	55,510	72,716	53,954	54,994	51,341	238,875	233,005	206,705
Federal income tax expense (benefit)	213	(242)	1,076	(75)	1,921	952	358	494	972	3,725	2,138
Net income (loss)	(2,193)	103	(1,914)	425	(11,176)	2,324	1,150	1,197	$ (3,579)	$ (6,505)	$ 4,793
Common Class A [Member]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (2,193)	$ 103	$ (1,914)	$ 425	$ (11,176)	$ 2,324	$ 1,150	$ 1,197
Basic earnings per share	$ (0.04)	$ 0.00	$ (0.04)	$ 0.01	$ (0.22)	$ 0.04	$ 0.03	$ 0.02
Diluted earnings per share	(0.04)	0.00	(0.04)	0.01	(0.22)	0.04	0.03	0.02
Common Class B [Member]
Basic earnings per share	(0.02)	0.00	(0.02)	0.00	(0.12)	0.03	0.01	0.01
Diluted earnings per share	$ (0.02)	$ 0.00	$ (0.02)	$ 0.00	$ (0.12)	$ 0.03	$ 0.01	$ 0.01