Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Accrued stock-based compensation (stock performance rights)	$ 14,437	$ 14,908
Accrued compensation	9,794	9,238
Accrued and withheld taxes, other than income taxes	3,788	4,387
Accrued profit sharing	240	916
Accrued severance	1,103	778
Deferred revenue	822	648
Accrued health benefits	732	578
Other	7,576	7,858
Total accrued liabilities	$ 38,492	$ 39,311