(Accumulated Amortization of Intangible Assets Schedule) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 96,561	$ 96,561	$ 96,561
Finite-Lived Intangible Assets, Accumulated Amortization	(38,237)	(35,933)	(28,139)
Finite-Lived Intangible Assets, Net	58,324	60,628	68,422
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	(30,194)	(28,304)	(22,073)
Finite-Lived Intangible Assets, Net	52,129	54,019	60,250
Lease Agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	238	238	238
Finite-Lived Intangible Assets, Accumulated Amortization	(220)	(212)	(185)
Finite-Lived Intangible Assets, Net	18	26	53
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	(7,823)	(7,417)	(5,881)
Finite-Lived Intangible Assets, Net	$ 6,177	$ 6,583	$ 8,119