Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Changes in operating assets and liabilities
Accounts receivable, net	$ (12,329)	$ 3,238	$ (12,585)
Inventories	1,568	1,750	(913)
Other current assets and other assets	(2,611)	4,459	661
Income taxes receivable	1,248	12,700	121
Accounts payable	(6,725)	6,511	(3,562)
Accrued expenses and other current liabilities	(1,242)	(16,550)	(12,929)
Accrued compensation related costs	5,780	1,713	16,843
Other liabilities	(1,883)	(3,980)	(2,271)
Operating lease liabilities, net of amortization of right-of-use assets	262
Changes in operating assets and liabilities on cash flows from operating activities	(15,932)	9,841	(14,635)
Operating lease liabilities	(36,911)
Amortization of right-of-use assets	37,173
Operating lease liabilities, net of amortization of right-of-use assets	262
Cash paid during the period for:
Interest paid	29,192	31,312	48,437
Income tax (refunds received) paid	5,100	(11,131)	725
Non-cash financing and investing activities:
Issuance of seller notes and working capital adjustments in connection with acquisitions	7,885	1,120
Purchase of property, plant and equipment in accounts payable at period end	2,998	5,018	2,119
Purchase of property, plant and equipment through vendor financing	$ 2,200
Additions to property, plant and equipment acquired through financing obligations		1,523	1,484
Retirements of financed property, plant and equipment and related financing obligations		$ 4,460	$ 811