Unaudited Condensed Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 26,730	$ 20,768
Other Comprehensive Income, Net of Tax
Unrealized gains on available-for-sale securities	14,603	571
Reclassification adjustment for losses included in net income	73	137
Net unrealized gains on available-for-sale securities	14,676	708
Tax effect	(5,680)	(275)
Net of tax amount	8,996	433
Unrealized (losses) gains on derivatives used for cash flow hedges	(5,479)	2,752
Tax effect	2,126	(1,072)
Net of tax amount	(3,353)	1,680
Total other comprehensive income, net of tax	5,643	2,113
Total Comprehensive Income	$ 32,373	$ 22,881