Restructuring Charges (Details) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) employee	Jun. 30, 2014 USD ($)
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring charge (credit)		$ 675	$ 1,508	$ 736	$ 1,406
2014 Plan
Restructuring Charges
Expected number of employees to be impacted by the restructuring | employee				280
Expected restructuring charges		26,939		$ 26,939
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring liability, as of January 1, 2015				16,352
Restructuring charge (credit)		632		657
Non-cash items				(205)
Cash paid				(9,272)
Foreign exchange rate changes				(774)
Restructuring liability, as of June 30, 2015		6,758		6,758
Restructuring charges, incurred to date		25,124		25,124
2014 Plan | North America
Restructuring Charges
Expected restructuring charges		1,011		1,011
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring charge (credit)		0		0
Restructuring charges, incurred to date		1,011		1,011
2014 Plan | International
Restructuring Charges
Expected restructuring charges		18,400		18,400
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring charge (credit)		426		426
Restructuring charges, incurred to date		18,257		18,257
2014 Plan | Other
Restructuring Charges
Expected restructuring charges		339		339
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring charge (credit)		0		25
Restructuring charges, incurred to date		339		339
2014 Plan | Corporate
Restructuring Charges
Expected restructuring charges		7,189		7,189
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring charge (credit)		206		206
Restructuring charges, incurred to date		5,517		5,517
2014 Plan | Employee Severance and Termination
Restructuring Charges
Expected restructuring charges		20,000		20,000
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring liability, as of January 1, 2015				15,152
Restructuring charge (credit)				657
Non-cash items				(205)
Cash paid				(8,072)
Foreign exchange rate changes				(774)
Restructuring liability, as of June 30, 2015		6,758		6,758
2014 Plan | Professional Fees, Office Closures and Other
Restructuring Charges
Expected restructuring charges		7,000		7,000
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring liability, as of January 1, 2015				1,200
Restructuring charge (credit)				0
Non-cash items				0
Cash paid				(1,200)
Foreign exchange rate changes				0
Restructuring liability, as of June 30, 2015		0		0
2012 Plan
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring charge (credit)		32		68
Restructuring charges, incurred to date	[1]	14,017		14,017
2012 Plan | North America
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring charge (credit)		(6)		(5)
Restructuring charges, incurred to date	[1]	1,697		1,697
2012 Plan | International
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring charge (credit)		0		0
Restructuring charges, incurred to date	[1]	8,851		8,851
2012 Plan | Corporate
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring charge (credit)	[2]	38		73
Restructuring charges, incurred to date	[1],[2]	3,469		3,469
2012 Plan | Office Closures
Changes in restructuring liabilities, recorded in other accrued expenses
Restructuring liability, as of January 1, 2015				1,694
Restructuring charge (credit)				68
Cash paid				(609)
Foreign exchange rate changes				(14)
Restructuring liability, as of June 30, 2015		$ 1,139		$ 1,139

[1] Our restructuring charges, particularly lease-related office closure costs, are subject to estimate. If we are unable to find tenants for vacated offices or sub-lease terms are different from our assumptions, our actual restructuring charges will differ from our current estimates.

[2] Corporate restructuring charges include costs for administrative facility consolidation.