Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement of Other Comprehensive Income [Abstract]
Net income	$ 22,702	$ 18,981	$ 43,470	$ 35,314
Other Comprehensive (Loss) Income, Net of Tax
Unrealized (losses) gains on available-for-sale securities	(56,256)	13,214	(55,685)	23,232
Reclassification adjustment for gains included in net income	(241)	0	(104)	0
Net unrealized (losses) gains on securities	(56,497)	13,214	(55,789)	23,232
Tax effect	21,977	(5,140)	21,702	(9,037)
Net of tax amount	(34,520)	8,074	(34,087)	14,195
Unrealized gains (losses) on derivatives used for cash flow hedges	12,810	(9,051)	15,562	(5,939)
Tax effect	(4,983)	3,521	(6,055)	2,310
Net of tax amount	7,827	(5,530)	9,507	(3,629)
Total other comprehensive (loss) income, net of tax	(26,693)	2,544	(24,580)	10,566
Total Comprehensive (Loss) Income	$ (3,991)	$ 21,525	$ 18,890	$ 45,880