Acquisitions (Details) $ in Thousands, NZD in Millions, AUD in Millions	3 Months Ended
	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 AUD	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Mar. 31, 2016 NZD	Jan. 31, 2016
Business Acquisition [Line Items]
Mandatorily redeemable noncontrolling interests	$ 0	$ 18,981
(Loss)/gain on investments and other, net	(251)				$ 309
Business Combination, Acquisition Related Costs	$ 1,000				$ 100
PIQ Acquisition [Member]
Business Acquisition [Line Items]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage	40.00%					40.00%	40.00%
Mandatorily redeemable noncontrolling interests	$ 19,000					NZD 27.8
RELS LLC [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		65,000
(Loss)/gain on investments and other, net		34,300
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		27,000
Goodwill, Acquired During Period		23,100
Business Acquisition, Goodwill, Expected Tax Deductible Amount		11,500
Cordell Information Pty Ltd [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		49,100	AUD 70.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		14,300
Goodwill, Acquired During Period		$ 31,900
Landsafe [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross				$ 122,000
Goodwill, Acquired During Period				$ 64,600
Property, Plant and Equipment [Member] | RELS LLC [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		10 years	10 years
Property, Plant and Equipment [Member] | Cordell Information Pty Ltd [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		10 years	10 years
Customer Lists [Member] | RELS LLC [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		10 years	10 years
Finite-lived Intangible Assets Acquired		$ 48,400
Customer Lists [Member] | Cordell Information Pty Ltd [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		8 years	8 years
Finite-lived Intangible Assets Acquired		$ 5,500
Customer Lists [Member] | Landsafe [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				10 years
Finite-lived Intangible Assets Acquired				$ 53,400
Trade Names [Member] | Cordell Information Pty Ltd [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		4 years	4 years
Finite-lived Intangible Assets Acquired		$ 600
Other Intangible Assets [Member] | RELS LLC [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		10 years	10 years
Finite-lived Intangible Assets Acquired		$ 5,000
Other Intangible Assets [Member] | Landsafe [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life				10 years
Finite-lived Intangible Assets Acquired				$ 4,300
RELS LLC [Member]
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage					50.10%