LHFI and Allowance for Loan Losses, LHFI - Additional Information (Details 3) $ in Thousands	12 Months Ended
	Dec. 31, 2017 Factor Loan Scale	Dec. 31, 2015 USD ($)
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Number of loan types for commercial portfolio | Loan	9
Number of risk rate factors for commercial loans | Factor	450
Length of loss emergence period in the quantitative portion of the allowance for loan loss methodology for commercial LHFI		1 year 6 months
Additional provision amount quantitative portion of the allowance for loan loss methodology for commercial LHFI		$ 2,300
Additional provision amount quantitative portion of the allowance for loan loss methodology for commercial LHFI due to incorporate third-party default data		1,300
Minimum score for qualitative risk factor | Scale	0
Maximum score for qualitative risk factor | Scale	100
Amount of provision recapture resulting from the elimination of cap and floors for criticized risk ratings in the qualitative portion of the allowance for loan loss methodology for commercial LHFI		1,800
Amount of additional provision expense resulting from market region distribution related to qualitative portion of the allowance for loan loss methodology for commercial LHFI		2,100
Amount of additional provision recapture resulting from market region distribution related to quantitative portion of the allowance for loan loss methodology for commercial LHFI		785
Length of loss emergence period in the qualitative portion of the allowance for loan loss methodology for commercial LHFI to observe the maximum observed gross historical losses	3 years
Additional provision due to revision of methodology to incorporate the use of maximum observed gross historical losses		4,400
Amount of provision recapture resulting from revision to loan facility risk component related to qualitative portion of the allowance for loan loss methodology for commercial LHFI		2,100
Amount of provision recapture resulting from market region distribution related to quantitative portion of the allowance for loan loss methodology for consumer LHFI regarding consumer mortgage portfolio		455
Additional provision amount qualitative portion of the allowance for loan loss methodology for consumer LHFI to incorporate the use of maximum observed gross historical losses		750
Number of unique qualitative factors used to analyze consumer loans | Factor	5
Number of loan types for consumer portfolio | Loan	5
Commercial and Industrial Loans [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Additional provision due to revision of methodology		1,100
Consumer Loans [Member]
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Additional provision due to revision of methodology		$ 2,200