Leases and Commitments - Sale Leaseback Transactions (Details) - USD ($)		12 Months Ended
	Apr. 23, 2015	Dec. 31, 2019	Dec. 31, 2018
Sale Leaseback Transaction [Line Items]
Sale Leaseback Transaction, Net Proceeds, Investing Activities		$ 23,000,000
Sale Leaseback Transaction, Annual Rental Payments		$ 2,275,000
Sale Leaseback Transaction, Lease Term		20 years
Sale Leaseback Transaction, Lease Terms		Each of the four lease agreements contains three 10-year renewals with the rent for each option term based on the greater of the then-current fair market rent for each property or the then- current rate and increasing annually by the applicable CPI. Under the terms of the lease agreements, the company is responsible for all taxes, insurance and utilities. The company is permitted to sublet the properties; however, the properties are currently being utilized exclusively by the company and there is no current subletting. The company is required to adequately maintain each of the properties and any leasehold improvements will be amortized over the lesser of the lives of the improvements or the remaining lease lives, consistent with any other company leases.
Deferred gain on sale leaseback	$ 7,414,000	$ 5,819,000	$ 6,124,000
Sale Leaseback Transaction, Immediate Loss Recognized	257,000
Capital Lease Obligations	$ 32,339,000