Goodwill and Intangible Assets (Schedule of Goodwill and Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Goodwill and Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$ 919	$ 919	$ 919	$ 919
Other intangible assets, net	26,924	22,792	26,924	22,792		$ 30,459
Goodwill and Intangible Assets [Roll Forward]
Total goodwill, beginning of period			382,537
Total goodwill, end of period	382,537	343,952	382,537	343,952
CDI current period amortization	(1,718)	(1,480)	(3,535)	(3,060)
Total goodwill and intangible assets, end of period	409,461	366,744	$ 409,461	366,744
Core Deposits [Member]
Goodwill and Intangible Assets [Line Items]
Estimated life of CDI, in years			10 years
Goodwill and Intangible Assets [Roll Forward]
Gross core deposit intangible balance, beginning of period					$ 58,598	58,598	$ 47,698	$ 47,698
Accumulated amortization at beginning of period					$ (30,875)	$ (29,058)	$ (24,344)	$ (22,765)
Core deposit intangible, net, beginning of period	27,723	23,354	$ 29,540	24,933
CDI current period amortization	(1,718)	(1,481)	(3,535)	(3,060)
Total core deposit intangible, end of period	$ 26,005	$ 21,873	$ 26,005	$ 21,873