Intangible Assets (Amortization Expense of Core Deposit Intangible Assets) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Carrying amount	$ 34,270	$ 41,201	$ 34,270	$ 41,201	$ 38,104
Amortization of intangible assets			4,751	3,787
Core deposit intangible assets [Member]
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Gross original amount	40,055	39,355	40,055	39,355	40,055
Accumulated amortization	15,626	11,002	15,626	11,002	13,401
Carrying amount	24,429	28,353	24,429	28,353	$ 26,654
Amortization of intangible assets	$ 1,113	$ 952	$ 2,225	$ 1,743