Goodwill and Other Intangible Assets - Schedule of Amortizing Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 33,428	$ 33,460
Accumulated Amortization	24,165	22,111
Net Carrying Amount	9,263	11,349
Amortization of intangible assets	1,932	2,090	$ 2,013
Core deposit intangible
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	18,774	18,774
Accumulated Amortization	14,302	13,129
Net Carrying Amount	4,472	5,645
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,878	8,942
Accumulated Amortization	5,339	4,737
Net Carrying Amount	3,539	4,205
Other intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5,776	5,744
Accumulated Amortization	4,524	4,245
Net Carrying Amount	$ 1,252	$ 1,499