Investments - Gain (Loss) on Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Gain (Loss) on Investments [Line Items]
Net realized investment gains	$ 5,092	$ 640	$ 8,984	$ 27,133
Gross realized gains, gross realized losses and impairment losses [Abstract]
Gains on sales	6,168	720	11,677	28,711
Losses on sales	(1,076)	(80)	(2,693)	(1,578)
Net realized investment gains	5,092	640	8,984	27,133
Fixed maturities
Gain (Loss) on Investments [Line Items]
Net realized investment gains	1,511	638	5,397	27,123
Gross realized gains, gross realized losses and impairment losses [Abstract]
Net realized investment gains	1,511	638	5,397	27,123
Equity securities
Gain (Loss) on Investments [Line Items]
Net realized investment gains	3,581	2	3,587	10
Gross realized gains, gross realized losses and impairment losses [Abstract]
Net realized investment gains	$ 3,581	$ 2	$ 3,587	$ 10