Intangible Assets (Amortization Expense of Core Deposit Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Carrying amount	$ 36,266	$ 31,655	$ 38,104
Amortization of intangible assets	2,169	1,825
Core deposit intangible assets [Member]
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Gross original amount	40,055	30,122	40,055
Accumulated amortization	14,513	10,050	13,401
Carrying amount	25,542	20,072	$ 26,654
Amortization of intangible assets	$ 1,112	$ 791