Loans and Loans Held for Sale - Summary of Restructured Loans (Details) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2017 USD ($) tdr	Mar. 31, 2016 USD ($) tdr	Dec. 31, 2016 USD ($)
Financing Receivable, Modifications [Line Items]
Restructured loans	[1]	$ 438	$ 2,614
Number of troubled debt restructuring loans returned back to accruing status | tdr		0	0
Performing
Financing Receivable, Modifications [Line Items]
Restructured loans		$ 13,086		$ 13,423
Performing | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Restructured loans		2,715		2,994
Performing | Commercial And Industrial
Financing Receivable, Modifications [Line Items]
Restructured loans		1,361		1,387
Performing | Commercial Construction
Financing Receivable, Modifications [Line Items]
Restructured loans		2,959		2,966
Performing | Residential Mortgage
Financing Receivable, Modifications [Line Items]
Restructured loans		2,242		2,375
Performing | Home Equity Loan
Financing Receivable, Modifications [Line Items]
Restructured loans		3,793		3,683
Performing | Installment And Other Consumer
Financing Receivable, Modifications [Line Items]
Restructured loans		16		18
Nonperforming
Financing Receivable, Modifications [Line Items]
Restructured loans		10,324		11,598
Nonperforming | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Restructured loans		625		646
Nonperforming | Commercial And Industrial
Financing Receivable, Modifications [Line Items]
Restructured loans		3,942		4,493
Nonperforming | Commercial Construction
Financing Receivable, Modifications [Line Items]
Restructured loans		427		430
Nonperforming | Residential Mortgage
Financing Receivable, Modifications [Line Items]
Restructured loans		4,321		5,068
Nonperforming | Home Equity Loan
Financing Receivable, Modifications [Line Items]
Restructured loans		1,003		954
Nonperforming | Installment And Other Consumer
Financing Receivable, Modifications [Line Items]
Restructured loans		6		7
Financing Receivable
Financing Receivable, Modifications [Line Items]
Restructured loans		23,410		25,021
Financing Receivable | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Restructured loans		3,340		3,640
Financing Receivable | Commercial And Industrial
Financing Receivable, Modifications [Line Items]
Restructured loans		5,303		5,880
Financing Receivable | Commercial Construction
Financing Receivable, Modifications [Line Items]
Restructured loans		3,386		3,396
Financing Receivable | Residential Mortgage
Financing Receivable, Modifications [Line Items]
Restructured loans		6,563		7,443
Financing Receivable | Home Equity Loan
Financing Receivable, Modifications [Line Items]
Restructured loans		4,796		4,637
Financing Receivable | Installment And Other Consumer
Financing Receivable, Modifications [Line Items]
Restructured loans		$ 22		$ 25

[1] Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.