Goodwill and Other Intangible Assets (Rollforward of Other Intangible Assets) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Other Intangible Assets [Line Items]
Other intangible assets, gross carrying amount				$ 354,200
Accumulated amortization				(103,800)
Other Intangible Assets [Rollforward]
Other intangible assets, net, beginning balance		$ 250,373
Amortization expense		(7,300)	$ (4,600)
Currency translation adjustments, other intangible assets		(6,900)
Other intangible assets, net, ending balance		236,231
Customer Relationships and Backlog [Member]
Other Intangible Assets [Line Items]
Other intangible assets, amortizing, gross carrying amount				199,800
Accumulated amortization				(90,300)
Other Intangible Assets [Rollforward]
Other intangible assets, net, amortizing, beginning balance		109,500
Amortization expense		(6,800)
Currency translation adjustments, amortizing intangible assets		(1,400)
Other intangible assets, net, amortizing, ending balance		101,300
Other Amortizing Intangible Assets [Member]
Other Intangible Assets [Line Items]
Other intangible assets, amortizing, gross carrying amount	[1]			26,300
Accumulated amortization	[1]			(13,500)
Other Intangible Assets [Rollforward]
Other intangible assets, net, amortizing, beginning balance	[1]	12,800
Amortization expense	[1]	(500)
Currency translation adjustments, amortizing intangible assets	[1]	(300)
Other intangible assets, net, amortizing, ending balance	[1]	12,000
Trade Names [Member]
Other Intangible Assets [Line Items]
Other intangible assets, non-amortizing, carrying amount		34,800		34,800
Other Intangible Assets [Rollforward]
Other intangible assets, non-amortizing, beginning balance		34,800
Currency translation adjustments, non-amortizing intangible assets		0
Other intangible assets, non-amortizing, ending balance		34,800
Pre-Qualifications [Member]
Other Intangible Assets [Line Items]
Other intangible assets, non-amortizing, carrying amount		93,300		$ 93,300
Other Intangible Assets [Rollforward]
Other intangible assets, non-amortizing, beginning balance		93,300
Currency translation adjustments, non-amortizing intangible assets		(5,200)
Other intangible assets, non-amortizing, ending balance		$ 88,100

[1] Consists principally of trade names and non-compete agreements.