Other Intangibles - Schedule of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 63,940	$ 61,798
Measurement period adjustment		2,142
Accumulated amortization	(52,666)	(49,074)
Total other intangibles	33,203	14,866
Core deposits
Acquired Finite-Lived Intangible Assets [Line Items]
Intangibles acquired	18,164
Other intangibles
Acquired Finite-Lived Intangible Assets [Line Items]
Intangibles acquired	$ 3,765