Income Taxes - Income tax reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Statutory tax rate													21.00%	35.00%
Reconciliation of effective income tax amount
Tax at statutory rate													$ (105,310)	$ (33,905)	$ (94,693)
State income taxes													(7,666)	(6,557)	(4,219)
Foreign income taxes													4,390	1,228	305
Nondeductible transaction costs															27,311
Nondeductible goodwill impairment													61,699	9,002	10,497
Permanent differences													1,275	2,542	438
Litigation settlement													3,310	608	415
Changes in valuation allowance													30,064	19,433	(6,159)
Unremitted earnings													1,604	4,735
Changes in U.S. tax rates															(4,784)
Deemed mandatory repatriation															7,441
GILTI Inclusion													3,772	2,289
Expiration of tax attributes													10,807	8,353
Other													3,697	625	2,380
Income tax expense (benefit)	$ 1,953	$ (3,769)	$ 4,738	$ 4,720	$ 3,442	$ (733)	$ 1,619	$ 4,025	$ 9,458	$ 5,644	$ 5,689	$ 4,911	7,642	8,353	$ (61,068)
Tax impacts of GILTI													18,000	2,300
Tax expense related to BEAT													$ 0	$ 1,300