Reinsurance - Summary of Reinsurance Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Gross Amount
Premiums written and contract deposits, Gross Amount	$ 305,864	$ 316,123	$ 594,680	$ 617,635
Premiums and contract charges earned, Gross Amount	209,892	200,351	417,629	400,806
Benefits, claims and settlement expenses, Gross Amount	170,459	168,218	322,427	315,489
Ceded to Other Companies
Premiums written and contract deposits, Ceded to Other Companies	5,483	5,643	10,997	11,153
Premiums and contract charges earned, Ceded to Other Companies	5,505	5,665	11,033	11,199
Benefits, claims and settlement expenses, Ceded to Other Companies	3,330	3,185	12,344	7,068
Assumed from Other Companies
Premiums written and contract deposits, Assumed from Other Companies	1,341	1,134	2,047	1,864
Premiums and contract charges earned, Assumed from Other Companies	1,223	1,032	2,012	1,833
Benefits, claims and settlement expenses, Assumed from Other Companies	1,149	846	1,757	1,554
Net Amount
Premiums written and contract deposits, Net Amount	301,722	311,614	585,730	608,346
Premiums and contract charges earned, Net Amount	205,610	195,718	408,608	391,440
Benefits, claims and settlement expenses, Net Amount	$ 168,278	$ 165,879	$ 311,840	$ 309,975