Intangible Assets (Amortization Expense of Core Deposit Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Carrying amount	$ 41,201	$ 12,454	$ 41,201	$ 12,454	$ 33,080
Amortization of intangible assets			3,787	1,391
Core deposit intangible assets [Member]
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Gross original amount	39,355	18,659	39,355	18,659	31,550
Accumulated amortization	11,002	9,549	11,002	9,549	10,687
Carrying amount	28,353	9,110	28,353	9,110	$ 20,863
Amortization of intangible assets	$ 952	$ 446	$ 1,743	$ 891