Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Accumulated Other Comprehensive Income and (Loss), Pre-Tax Amount, Beginning of period	$ 2,640	$ 6,537	$ 150
Change in net unrealized gain (loss) on investments, Pre-Tax Amount	(629)	(3,070)	6,367
Reclassification adjustment for realized losses, Pre-Tax Amount	(547)	(827)	20
Accumulated Other Comprehensive Income and (Loss), Pre-Tax Amount, End of period	1,464	2,640	6,537
Accumulated Other Comprehensive Income (Loss), Tax (Expense) Benefit, Beginning of period	1,020	2,526	58
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	167	1,187	(2,460)
Reclassification adjustment for realized losses, Tax (Expense) Benefit	211	319	(8)
Accumulated Other Comprehensive Income (Loss), Tax (Expense) Benefit, End of period	642	1,020	2,526
Accumulated Other Comprehensive Income (Loss), Net-of-Tax Amount, Beginning of period	1,620	4,011	92
Change in net unrealized gain (loss) on investments, Net-of-Tax Amount	(462)	(1,883)	3,907
Reclassification adjustment for realized losses, Net-of-Tax Amount	(336)	(508)	12
Accumulated Other Comprehensive Income (Loss), Net-of-Tax Amount, End of period	$ 822	$ 1,620	$ 4,011