Fair Value of Financial Instruments - Rollforward of Level 3 Assets Measured on Recurring Basis (Details) - Fair Value, Recurring Measurements [Member] - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Level 3 assets, beginning of period		$ 717	$ 862	$ 783	$ 1,165
Net unrealized gains (losses) included in other comprehensive income		12	2	17	(4)
Realized gains (losses) and accretion (amortization) recognized in earnings, including OTTI		1		6
Purchases	[1]	4,183		4,183
Sales				(3)
Settlements		(25)	(35)	(98)	(111)
Transfers into Level 3		1,675		1,676	2
Transfers out of Level 3		(1)	(2)	(2)	(225)
Level 3 assets, end of period		$ 6,562	$ 827	$ 6,562	$ 827

[1] During the three and nine months ended September 30, 2016, purchases of Level 3 assets primarily consisted of newly issued fixed maturity securities in the third quarter for which observable inputs, most notably quoted prices, used to derive valuations are not yet readily available.