Loans - Summary of TDRs (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
Total TDRs	$ 71,086	$ 77,888
Commercial loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	53,474	58,842
Consumer loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	17,612	19,046
Accruing TDRs
Financing Receivable, Modifications [Line Items]
Total TDRs	43,025	48,782
Accruing TDRs | Commercial loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	29,383	34,484
Accruing TDRs | Consumer loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	13,642	14,298
Nonaccrual TDRs
Financing Receivable, Modifications [Line Items]
Total TDRs	28,061	29,106
Nonaccrual TDRs | Commercial loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	24,091	24,358
Nonaccrual TDRs | Consumer loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	$ 3,970	$ 4,748