Fair Value Measurement of Assets and Liabilities - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Impaired collateral dependent loans, charge-offs	$ 938,000	$ 0	$ 938,000	$ 0
Collateral dependent impaired loans, recorded investment	73,400,000		73,400,000
Specific valuation allowance allocations	29,700,000		29,700,000
Reported net carrying amount of impaired loans	43,700,000		$ 43,700,000
Valuation of loan servicing rights, prepayment rate			11.00%
Valuation of loan servicing rights, discount rate			9.50%
Net recoveries of net impairment charges	107,000	90,000	$ 84,000	317,000
Foreclosed assets measured at fair value upon initial recognition			5,600,000
Foreclosed asset charge-offs	653,000	649,000	1,400,000	1,200,000
Loss due to re-measurement of repossessed assets	$ 0	$ 0	$ 160,000	$ 145,000