Fair Value - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization Rates Utilized To Determine Fair Value Of Underlying Collateral Averaged Percentage	7.60%
Loans and Leases Receivable, Allowance	$ 28,118	$ 27,122	$ 24,562	$ 23,400
Loans Receivable [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	200
Other Real Estate Owned [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Receivable, Fair Value Disclosure	7,100	4,200
Loans and Leases Receivable, Allowance	2,700	$ 2,400
Other Real Estate, Disposals	3,100
Other Real Estate, Improvements	$ 2,000