Intangible Assets (Amortization Expense of Core Deposit Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Carrying amount	$ 39,864	$ 11,958	$ 39,864	$ 11,958	$ 33,080
Amortization of intangible assets			6,126	2,211
Core deposit intangible assets [Member]
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Gross original amount	40,055	18,659	40,055	18,659	31,550
Accumulated amortization	12,165	9,994	12,165	9,994	10,687
Carrying amount	27,890	8,665	27,890	8,665	$ 20,863
Amortization of intangible assets	$ 1,163	$ 445	$ 2,906	$ 1,336