Goodwill and Other Intangible Assets (Rollforward of Other Intangible Assets) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Other Intangible Assets [Line Items]
Other intangible assets, gross carrying amount				$ 329,300
Accumulated amortization				(129,900)
Other Intangible Assets [Rollforward]
Other intangible assets, net, beginning balance		$ 199,379
Amortization expense		(5,300)	$ (7,300)
Currency translation adjustments, other intangible assets		3,400
Other intangible assets, net, ending balance		197,503
Customer Relationships and Backlog [Member]
Other Intangible Assets [Line Items]
Other intangible assets, amortizing, gross carrying amount				195,400
Accumulated amortization				(114,600)
Other Intangible Assets [Rollforward]
Other intangible assets, net, amortizing, beginning balance		80,800
Amortization expense		(4,200)
Currency translation adjustments, amortizing intangible assets		600
Other intangible assets, net, amortizing, ending balance		77,200
Other Amortizing Intangible Assets [Member]
Other Intangible Assets [Line Items]
Other intangible assets, amortizing, gross carrying amount	[1]			25,700
Accumulated amortization	[1]			(15,300)
Other Intangible Assets [Rollforward]
Other intangible assets, net, amortizing, beginning balance	[1]	10,400
Amortization expense	[1]	(1,100)
Currency translation adjustments, amortizing intangible assets	[1]	100
Other intangible assets, net, amortizing, ending balance	[1]	9,400
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		73,400		$ 73,400
Other Intangible Assets [Rollforward]
Other intangible assets, non-amortizing, beginning balance		73,400
Currency translation adjustments, non-amortizing intangible assets		2,700
Other intangible assets, non-amortizing, ending balance		$ 76,100

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