CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Other comprehensive income (loss)
Net income	$ 32,391	$ 24,702	$ 107,346	$ 89,514
Amounts related to available-for-sale securities:
Change in net unrealized gains	(10,720)	(27,539)	22,465	(104,037)
Amounts related to cash flow hedges:
Change in net unrealized losses	97	(10,867)	(25,557)	9,136
Reclassification adjustment for amounts included in net income	5,826	3,698	15,932	13,548
Other comprehensive income (loss)	(4,797)	(34,708)	12,840	(81,353)
Comprehensive income (loss)	$ 27,594	$ (10,006)	$ 120,186	$ 8,161