Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income
Balance, beginning			$ 17,744	$ 9,645
Other comprehensive income before reclassification			(12,105)	12,918
Amounts reclassified from accumulated other comprehensive income			2,368	112
Net current period other comprehensive income	$ 2,567	$ (1,531)	(9,737)	13,030
Balance, end	8,007	22,675	8,007	22,675
Available-For-Sale Securities
Accumulated Other Comprehensive Income
Balance, beginning			27,945	8,485
Other comprehensive income before reclassification			(5,524)	19,936
Amounts reclassified from accumulated other comprehensive income			58	112
Net current period other comprehensive income			(5,466)	20,048
Balance, end	22,479	28,533	22,479	28,533
Derivatives Used for Cash Flow Hedges
Accumulated Other Comprehensive Income
Balance, beginning			(10,201)	1,160
Other comprehensive income before reclassification			(6,581)	(7,018)
Amounts reclassified from accumulated other comprehensive income			2,310	0
Net current period other comprehensive income			(4,271)	(7,018)
Balance, end	$ (14,472)	$ (5,858)	$ (14,472)	$ (5,858)