Fair Value Measurements - Recurring basis Level 3 rollforward (Details 2) - Recurring basis - Level 3 - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fixed maturities available-for-sale, Corporate debt securities
Recurring Level 3 financial assets and liabilities
Balance at the beginning of the period	$ 10,931	$ 15,542	$ 11,639	$ 4,538
Net income (loss)	0	0	0	0
Other comprehensive income (loss)	84	109	(280)	475
Settlements	(312)	(595)	(656)	(1,193)
Transfers into Level 3				11,236
Balance at the end of the period	10,703	15,056	10,703	15,056
Total gains (losses) for the period included in net income attributable to the change in unrealized gains and losses relating to assets and liabilities	0	0	0	0
Embedded Derivative Financial Instruments
Recurring Level 3 financial assets and liabilities
Balance at the beginning of the period	4,042	21,707	5,712	11,257
Net income (loss)	(5,553)	(8,980)	(3,883)	(19,430)
Other comprehensive income (loss)		0	0	0
Settlements			0	0
Transfers into Level 3				0
Balance at the end of the period	9,595	30,687	9,595	30,687
Total gains (losses) for the period included in net income attributable to the change in unrealized gains and losses relating to assets and liabilities	$ (5,553)	$ (8,980)	$ (3,883)	$ (19,430)