Goodwill and other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Beginning balance	$ 265,957	$ 263,634
Goodwill acquired	2,047	2,323
Goodwill adjustments	(2,565)
Ending balance	265,439	265,957	$ 263,634
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	41,312	48,926
Less: accumulated amortization	25,497	31,661
Net carrying amount	15,815	17,265
Amortization Expense [Abstract]
Amortization of intangible assets	3,928	4,864	$ 5,047
Future Amortization Expense [Abstract]
2016	3,300
2017	2,600
2018	1,900
2019	1,500
2020	1,100
Thereafter	$ 3,900
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible asset useful life	1 year
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible asset useful life	20 years
Core Deposits Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 8,975	19,401
Less: accumulated amortization	5,626	14,800
Net carrying amount	3,349	4,601
Identified Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	32,338	29,525
Less: accumulated amortization	19,872	16,861
Net carrying amount	$ 12,466	$ 12,664