Leases (Assets and Liabilities Balance Related to Finance and Operating Leases) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Finance lease right-of-use assets	$ 320	$ 389
Operating lease right-of-use assets	17,007	17,161
Finance lease obligations, current portion	192	198
Finance lease obligations, non-current portion	68	209
Total finance lease obligations	260	407
Operating lease obligations, current portion	2,723	2,810
Operating lease obligations, non-current portion	14,155	14,965
Total operating lease obligations	$ 16,878	$ 17,775
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, plant and equipment, net of accumulated depreciation of $365,671 and $367,850	Property, plant and equipment, net of accumulated depreciation of $365,671 and $367,850
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Other long-term assets	Other long-term assets
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other accrued liabilities	Other accrued liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other long-term liabilities	Other long-term liabilities
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Other accrued liabilities	Other accrued liabilities
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other long-term liabilities	Other long-term liabilities