Other Intangibles - Schedule of Core Deposit and Other Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 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	(54,721)	(49,074)
Core deposit intangible and other intangibles reduction
Core Deposit and Other Intangibles	31,148	14,866
Core deposits
Acquired Finite-Lived Intangible Assets [Line Items]
Intangibles acquired	18,164
Other intangible
Acquired Finite-Lived Intangible Assets [Line Items]
Intangibles acquired	$ 3,765