Goodwill and Other Intangible Assets Goodwill and Other Intangible Assets-Accumulated Amortization of Intangible Assets Schedule (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 96,561	$ 96,561	$ 96,561
Finite-Lived Intangible Assets, Accumulated Amortization	(33,335)	(25,541)	(22,608)
Finite-Lived Intangible Assets, Net	63,226	71,020	73,953
Core Deposits
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	82,323	82,323	82,323
Finite-Lived Intangible Assets, Accumulated Amortization	(26,227)	(19,996)	(17,712)
Finite-Lived Intangible Assets, Net	56,096	62,327	64,611
Lease Agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	238	238	238
Finite-Lived Intangible Assets, Accumulated Amortization	(203)	(176)	(167)
Finite-Lived Intangible Assets, Net	35	62	71
Customer Relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	14,000	14,000	14,000
Finite-Lived Intangible Assets, Accumulated Amortization	(6,905)	(5,369)	(4,729)
Finite-Lived Intangible Assets, Net	$ 7,095	$ 8,631	$ 9,271