Reinsurance - Summary of Reinsurance Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Gross Amount
Premiums written and contract deposits, Gross Amount	$ 342,268	$ 322,428	$ 936,948	$ 940,063
Premiums and contract charges earned, Gross Amount	210,953	202,988	628,582	603,794
Benefits, claims and settlement expenses, Gross Amount	163,912	135,508	486,339	450,997
Ceded to Other Companies
Premiums written and contract deposits, Ceded to Other Companies	5,370	5,189	16,367	16,342
Premiums and contract charges earned, Ceded to Other Companies	5,385	5,216	16,418	16,415
Benefits, claims and settlement expenses, Ceded to Other Companies	3,207	1,831	15,551	8,899
Assumed from Other Companies
Premiums written and contract deposits, Assumed from Other Companies	1,199	1,116	3,246	2,980
Premiums and contract charges earned, Assumed from Other Companies	1,252	1,163	3,264	2,996
Benefits, claims and settlement expenses, Assumed from Other Companies	1,141	1,218	2,898	2,772
Net Amount
Premiums written and contract deposits, Net Amount	338,097	318,355	923,827	926,701
Premiums and contract charges earned, Net Amount	206,820	198,935	615,428	590,375
Benefits, claims and settlement expenses, Net Amount	$ 161,846	$ 134,895	$ 473,686	$ 444,870