Goodwill and Intangible Assets (Schedule of Goodwill and Intangible Assets) (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Mar. 31, 2011	Dec. 31, 2010	Mar. 31, 2010	Dec. 31, 2009
Goodwill and Intangible Assets
Total goodwill, beginning of period	$ 109,639	$ 109,639	$ 109,639	$ 95,519
Established through acquisitions	9,704	0	9,704	14,120
Total goodwill, end of period	119,343	109,639	119,343	109,639
Gross core deposit intangible balance, beginning of period					26,651	26,651	26,651	8,896
Accumulated amortization, beginning of period	(8,939)	(4,820)	(7,955)	(4,033)
Core deposit intangible, net, beginning of period	17,712	21,831	18,696	4,863
Established through acquisitions	1,846	0	1,846	17,755
CDI current period amortization	(956)	(1,055)	(1,940)	(1,842)
Total core deposit intangible, end of period	18,602	20,776	18,602	20,776
Total goodwill and intangible assets, end of period	$ 137,945	$ 130,415	$ 137,945	$ 130,415