Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Payables and Accruals [Abstract]
Accrued salaries, wages and related employee benefits	$ 35,311	$ 30,214
Contingent consideration, current portion	915	1,300
Accrued workers’ compensation and health benefits	4,001	3,948
Deferred revenue	8,213	6,538
Pension accrual	2,519	2,519
Right-of-use liability - Operating	10,212	10,348
Other accrued expenses	26,301	23,633
Accrued expenses and other current liabilities	$ 87,472	$ 78,500