CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Other comprehensive income (loss)
Net income	$ 36,564	$ 29,894	$ 74,955	$ 64,812
Amounts related to available-for-sale securities:
Change in net unrealized gains	16,492	(68,793)	33,185	(76,498)
Amounts related to cash flow hedges:
Change in net unrealized losses	(12,998)	17,524	(25,654)	20,003
Reclassification adjustment for amounts included in net income	5,384	4,416	10,106	9,850
Other comprehensive income (loss)	8,878	(46,853)	17,637	(46,645)
Comprehensive income (loss)	$ 45,442	$ (16,959)	$ 92,592	$ 18,167