Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accrued Expenses and Other Current Liabilities
Payroll and related costs	$ 10,240	$ 10,382
Employee benefits	7,642	6,097
Accrued warranty	3,392	3,941
Interest rate swaps	4,075	1,522
Other	5,482	4,554
Accrued expenses and other current liabilities	$ 30,831	$ 26,496