Income Taxes - Effective Income Tax Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended							6 Months Ended		9 Months Ended		12 Months Ended
	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 Tax Disclosure [Abstract]
Tax (benefit) provision at U.S. federal income tax rate												$ (1,342)	$ (16,239)	$ 9,506
State income taxes, net of federal income tax effect												(775)	(307)	883
Federal, state and international deferred tax rate change												1,222	1,135	(4,907)
Transition tax												0	(924)	5,323
Effect of non-US operations												(1,859)	(2,424)	(2,228)
Nontaxable contingent liability fair value changes and goodwill impairment												0	11,254	237
Research and development credit												(202)	(40)	(38)
Change in valuation allowances												(98)	3,973	2,103
Prior year provision to return adjustment												(57)	942	(581)
Write-off of deferred taxes and tax receivables												1,961	431	70
Nondeductible expense and other												904	428	889
Tax reform global intangible low-taxed income												3,178	1,124	0
Tax reform BEAT												768	0	0
Provision (benefit) for income taxes	$ (1,250)	$ 2,468	$ (1,414)	$ (1,536)	$ (243)	$ 625	$ 506	$ 1,053	$ 1,131	$ (197)	$ 889	$ 3,700	$ (647)	$ 11,257