Leases (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019
Lessee, Lease, Description [Line Items]
Operating lease liabilities	$ 20,823,000		$ 20,203,000
Operating lease right-of-use assets	$ 19,239,000		18,651,000
Operating lease, weighted average remaining lease term	10 years 10 months 10 days
Lessee, operating lease, discount rate	3.49%
Operating lease, lease not yet commenced	$ 0
Accounting Standards Update 2016-02
Lessee, Lease, Description [Line Items]
Operating lease liabilities			20,200,000
Operating lease right-of-use assets			$ 18,700,000
Rent expense		$ 758,000
Related Parties Lease Transaction
Lessee, Lease, Description [Line Items]
Sale leaseback transaction	$ 0