Related Party Transactions - Income Statement Related Party Amounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transactions [Abstract]
Premium income, net of related party premiums ceded of $20,033, $17,774, and $15,731	$ 61,368	$ 66,928	$ 68,722
Life and other policy benefits, net of reinsurance recoveries of $10,313, $8,862, and $6,494	179,748	189,125	193,215
Decrease in future policy benefits	(70,654)	(88,639)	(52,842)
Related party premiums ceded	20,003	17,774	15,731
Reinsurance recoveries	$ 10,313	$ 8,862	$ 6,494