Variable Interest Entities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Classification of carrying amount of assets and liabilities of VIE [Abstract]
Proceeds from Issuance of Subordinated Long-term Debt	$ 133,000
Low Income Housing Partnerships [Member] | Other Assets [Member]
Classification of carrying amount of assets and liabilities of VIE [Abstract]
Maximum Loss Exposure	23,912	$ 24,150
Liability Recognized	0	0
Trust Preferred Issuances [Member] | Subordinated Debt [Member]
Classification of carrying amount of assets and liabilities of VIE [Abstract]
Liability Recognized	132,995	82,476
Commercial Troubled Debt Restructurings [Member] | Loans [Member]
Classification of carrying amount of assets and liabilities of VIE [Abstract]
Maximum Loss Exposure	3,760	11,572
Liability Recognized	$ 0	$ 0