Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Loss
Balance, beginning			$ (9,427)	$ (1,979)
Other comprehensive income (loss) before reclassification			52,766	(19,665)
Reclassification adjustments for (gains) losses included in net income			109	1,362
Total other comprehensive income (loss), net of tax	$ 19,561	$ (3,259)	52,875	(18,303)
Balance, end	43,448	(20,282)	43,448	(20,282)
Available-For-Sale Debt Securities
Accumulated Other Comprehensive Loss
Balance, beginning			(6,613)	5,031
Other comprehensive income (loss) before reclassification			56,988	(24,195)
Reclassification adjustments for (gains) losses included in net income			(266)	259
Total other comprehensive income (loss), net of tax			56,722	(23,936)
Balance, end	50,109	(18,905)	50,109	(18,905)
Derivatives Used for Cash Flow Hedges
Accumulated Other Comprehensive Loss
Balance, beginning			(2,814)	(7,010)
Other comprehensive income (loss) before reclassification			(4,222)	4,530
Reclassification adjustments for (gains) losses included in net income			375	1,103
Total other comprehensive income (loss), net of tax			(3,847)	5,633
Balance, end	$ (6,661)	$ (1,377)	$ (6,661)	$ (1,377)