Income Taxes - Deferred Tax Assets and Liabilities due to Temporary Differences (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Reserve for receivables	$ 1,221	$ 625
Accrued liabilities and inventory reserves	2,703	3,231
Net operating loss carryforward	25,615	31,555
Unrealized losses on interest rate swap contracts	12,016	1,338
Share-based compensation expense	3,808	3,044
Asset retirement obligations	819	1,101
Tangible and intangible assets	21,561	18,491
Deferred revenue	4,280	4,294
Other	2,992	4,057
Subtotal	75,015	67,736
Valuation allowance	(18,622)	(11,443)
Noncurrent deferred tax assets	56,393	56,293
Tangible and intangible assets	(87,539)	(88,017)
Asset retirement obligations	(30)	(29)
Unrealized gain on interest rate swap contracts	0	0
Other	(2,926)	(1,966)
Noncurrent deferred tax liabilities	(90,495)	(90,012)
Net deferred tax liability	$ (34,102)	$ (33,719)