Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income, Changes [Roll Forward]
Accumulated other comprehensive income (loss), balance beg of period	$ 254
Other comprehensive income (loss), net of tax	(684)	$ 3,792	$ (5,464)
Accumulated other comprehensive income (loss), balance at end of period	(430)	254
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income, Changes [Roll Forward]
Accumulated other comprehensive income (loss), balance beg of period	254	(3,538)	1,926
Other comprehensive income (loss), before reclassifications, net of tax	(730)	3,887
Reclassification from accumulated other comprehensive income, current period, net of tax	46	(95)
Other comprehensive income (loss), net of tax	(684)	3,792	(5,464)
Accumulated other comprehensive income (loss), balance at end of period	(430)	254	(3,538)
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Noncredit-related Unrealized Gains Losses on Securities with OTTI [Member]
Accumulated Other Comprehensive Income, Changes [Roll Forward]
Accumulated other comprehensive income (loss), balance beg of period	0	(1,439)	(1,759)
Other comprehensive income (loss), before reclassifications, net of tax	0	1,133
Reclassification from accumulated other comprehensive income, current period, net of tax	0	306
Other comprehensive income (loss), net of tax	0	1,439	320
Accumulated other comprehensive income (loss), balance at end of period	0	0	(1,439)
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Unrealized gains losses on securities without OTTI, net of tax [Member]
Accumulated Other Comprehensive Income, Changes [Roll Forward]
Accumulated other comprehensive income (loss), balance beg of period	416	(4,217)	4,146
Other comprehensive income (loss), before reclassifications, net of tax	(21)	5,085
Reclassification from accumulated other comprehensive income, current period, net of tax	(53)	(452)
Other comprehensive income (loss), net of tax	(74)	4,633	(8,363)
Accumulated other comprehensive income (loss), balance at end of period	342	416	(4,217)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income, Changes [Roll Forward]
Accumulated other comprehensive income (loss), balance beg of period	(162)	2,118	(461)
Other comprehensive income (loss), before reclassifications, net of tax	(709)	(2,331)
Reclassification from accumulated other comprehensive income, current period, net of tax	99	51
Other comprehensive income (loss), net of tax	(610)	(2,280)	2,579
Accumulated other comprehensive income (loss), balance at end of period	$ (772)	$ (162)	$ 2,118