Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 35,937	$ 14,536	$ 82,152	$ 43,034
Unrealized gain on available-for-sale securities:
Unrealized gain arising during the period	4,667	2,144	27,653	2,090
Reclassification adjustment for gain included in net income	(285)	(1,015)	(17,593)	(1,014)
Total change in unrealized gain on available-for-sale securities	4,382	1,129	10,060	1,076
Unrealized gain (loss) on cash flow hedge:
Unrealized loss arising during the period	0	(628)	0	(396)
Reclassification adjustment for loss included in net income	0	532	0	532
Total change in unrealized gain (loss) on cash flow hedge	0	(96)	0	136
Total other comprehensive income	4,382	1,033	10,060	1,212
Comprehensive income	$ 40,319	$ 15,569	$ 92,212	$ 44,246