Goodwill and Other Intangible Assets (Rollforward of Other Intangible Assets) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 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		$ (6,900)	$ (6,600)	(21,500)	$ (17,000)
Currency translation adjustments, other intangible assets				(10,100)
Other intangible assets, net, ending balance		218,761		218,761
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				(20,100)
Currency translation adjustments, amortizing intangible assets				(1,800)
Other intangible assets, net, amortizing, ending balance		87,600		87,600
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]			(1,400)
Currency translation adjustments, amortizing intangible assets	[1]			(400)
Other intangible assets, net, amortizing, ending balance	[1]	11,000		11,000
Trade Names [Member]
Other Intangible Assets [Line Items]
Other intangible assets, non-amortizing, carrying amount		34,800		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		34,800
Pre-Qualifications [Member]
Other Intangible Assets [Line Items]
Other intangible assets, non-amortizing, carrying amount		85,400		93,300		$ 93,300
Other Intangible Assets [Rollforward]
Other intangible assets, non-amortizing, beginning balance				93,300
Currency translation adjustments, non-amortizing intangible assets				(7,900)
Other intangible assets, non-amortizing, ending balance		$ 85,400		$ 85,400

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