Parent Holding Company Information Parent Statements of Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net Income	$ 26,546	$ 25,628	$ 22,702	$ 20,768	$ 20,758	$ 19,444	$ 18,981	$ 16,333	$ 95,644	$ 75,516	$ 17,471
Other Comprehensive (Loss) Income, Net of Tax
Unrealized (losses) gains on available-for-sale securities									(81,739)	31,617	63,190
Reclassification adjustment for losses (gains) included in net income									299	0	(346)
Net unrealized (losses) gains on securities									(81,440)	31,617	62,844
Tax effect									31,680	(12,300)	(24,444)
Net of tax amount									(49,760)	19,317	38,400
Unrealized gains (losses) on derivatives used for cash flow hedges									18,728	(7,926)	(8,906)
Tax effect									(7,285)	3,084	3,465
Net of tax amount									11,443	(4,842)	(5,441)
Total other comprehensive (loss) income, net of tax									(38,317)	14,475	32,959
Total Comprehensive Income									57,327	89,991	50,430
Parent Company
Net Income									95,644	75,516	17,091
Other Comprehensive (Loss) Income, Net of Tax
Unrealized (losses) gains on available-for-sale securities									(81,739)	31,617	63,190
Reclassification adjustment for losses (gains) included in net income									299	0	(346)
Net unrealized (losses) gains on securities									(81,440)	31,617	62,844
Tax effect									31,680	(12,300)	(24,444)
Net of tax amount									(49,760)	19,317	38,400
Unrealized gains (losses) on derivatives used for cash flow hedges									18,728	(7,926)	(8,906)
Tax effect									(7,285)	3,084	3,465
Net of tax amount									11,443	(4,842)	(5,441)
Total other comprehensive (loss) income, net of tax									(38,317)	14,475	32,959
Total Comprehensive Income									$ 57,327	$ 89,991	$ 50,050