Restructuring - Additional Information (Details) $ in Thousands	3 Months Ended		20 Months Ended
	Mar. 31, 2019 USD ($) employee	Mar. 31, 2018 USD ($)	Mar. 31, 2019 USD ($) employee
Restructuring Cost and Reserve [Line Items]
Restructuring and related charges	$ 1,086	$ 1,789
Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges, pre tax			$ 142,500
Restructuring charges, net of tax			128,500
Restructuring reserve, settled with cash	3,264	4,410	28,900
Restructuring reserve, settled without cash	$ (151)	2,408	113,600
Goodwill and long-lived asset impairment			86,400
Allowance for doubtful accounts receivable, write-offs			$ 27,200
Headcount reduction | employee			440
Expected number of additional positions eliminated | employee	50
Restructuring and related charges	$ 2,866	$ 5,244
Minimum | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Expected restructuring cash charges	12,000		$ 12,000
Maximum | Restructuring 2017
Restructuring Cost and Reserve [Line Items]
Expected restructuring cash charges	$ 16,000		$ 16,000