Restructuring - Summary of Accruals of Restructuring Programs (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jan. 01, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring Expenses (Reversals), Net		$ 18,738	$ (882)	$ 32,019	$ 24
Contractual Lease Obligations
Restructuring Reserve [Roll Forward]
Balance at January 1, 2019	$ 8,472			8,472
Restructuring Charges				0
Payments				0
Balance at June 30, 2019		0		0
Severance
Restructuring Cost and Reserve [Line Items]
Restructuring Expenses (Reversals), Net		1,856	$ 87	2,992	$ 601
Restructuring Reserve [Roll Forward]
Balance at January 1, 2019	651			651
Restructuring Charges				2,992
Payments				(2,427)
Balance at June 30, 2019		$ 1,216		1,216
Accounting Standards Update 2016-02 | Contractual Lease Obligations
Restructuring Reserve [Roll Forward]
Balance at January 1, 2019	0			0
Topic 842 Transition Adjustment	(8,472)
Accounting Standards Update 2016-02 | Severance
Restructuring Reserve [Roll Forward]
Balance at January 1, 2019	651			$ 651
Topic 842 Transition Adjustment	$ 0