Accrued Liabilities Long-term liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accrued Liabilities [Abstract]
Operating Lease, Liability, Noncurrent	$ 37,636	$ 41,019
Accrued Employee Benefits	1,150	1,183
Accrued Rent	1,397	1,462
Liabilities for contracts	270	337
Finance Lease, Liability, Noncurrent	2,284	2,388
Other Accrued Liabilities, Noncurrent	214	1,446
OTHER LONG-TERM LIABILITIES	$ 42,951	$ 47,835