Lease Commitments - Supplemental Balance Sheet and Cash Flow Information Related to Operating Leases (Details)	3 Months Ended
	Mar. 31, 2019 USD ($)
Leases [Abstract]
Operating lease right-of-use assets	$ 28,052,000
Operating lease liabilities	32,270,000
Cash paid for amounts included in the measurement of operating lease liabilities	1,512,000
Right-of-use assets obtained in exchange for new operating lease obligations	$ 0
Weighted average remaining lease term for operating leases	9 years
Weighted average discount rate for operating leases	4.69%