Income Taxes - Components of deferred income tax liabilities and assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2015	Dec. 31, 2018
Deferred income tax liabilities:
Book over tax basis of intangible and fixed assets	$ (77,088)		$ (94,648)
Unremitted foreign earnings	(6,339)		(4,735)
Lease Asset	(16,981)
Other, net	(2,571)		(4,079)
Total deferred income tax liabilities	(102,979)		(103,462)
Deferred income tax assets:
Allowance for doubtful accounts and receivable adjustments	1,498		1,676
Inventory	903		1,629
Accrued liabilities	11,608		9,433
Net operating loss and tax credit carryforwards	158,265		184,430
Tax deductible goodwill	8,066		3,147
Disallowed Interest Deduction	56,873		26,897
Lease Liability	18,127
Other, net	15,481		16,031
Total deferred income tax assets	270,820		243,243
Valuation allowance	(163,806)		(134,650)
Total net deferred income tax assets	4,036		$ 5,131
Increase (decrease) in valuation allowance	29,200
Federal
Deferred income tax assets:
Valuation allowance related to disallowed interest deduction	48,900
Valuation allowance related to limitation of utilization of NOL carryforwards	65,400
Increase (decrease) in valuation allowance		$ 3,500
State
Deferred income tax assets:
Valuation allowance related to disallowed interest deduction	7,200
Valuation allowance related to limitation of utilization of NOL carryforwards	5,800
Foreign.
Deferred income tax assets:
Valuation allowance related to disallowed interest deduction	$ 37,600