Acquisitions (Details) NZD in Millions, $ in Millions	1 Months Ended		3 Months Ended
	Apr. 30, 2016 USD ($)	Dec. 31, 2012 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Jan. 31, 2016 USD ($)	Jan. 31, 2016 NZD
Business Acquisition [Line Items]
Acquisition-related costs			$ 0.3	$ 1.0
FNC, Inc. [Member]
Business Acquisition [Line Items]
Cash paid at closing in acquisition	$ 400.0
Contingent consideration	8.0
Deferred tax liability acquired	89.7
FNC, Inc. [Member] | Property Intelligence [Member]
Business Acquisition [Line Items]
Goodwill acquired	225.7
Goodwill increase as a result of change in purchase price allocation		$ 14.2
FNC, Inc. [Member] | Property and equipment [Member]
Business Acquisition [Line Items]
Property and equipment acquired	$ 79.8
Estimated average life in years	12 years
FNC, Inc. [Member] | Client lists [Member]
Business Acquisition [Line Items]
Estimated average life in years	16 years
Finite-lived intangible assets acquired	$ 141.8
FNC, Inc. [Member] | Trade names [Member]
Business Acquisition [Line Items]
Estimated average life in years	19 years
Finite-lived intangible assets acquired	$ 15.9
FNC, Inc. [Member] | Non-compete agreements [Member]
Business Acquisition [Line Items]
Estimated average life in years	5 years
Finite-lived intangible assets acquired	$ 18.8
FNC, Inc. [Member] | Other Intangible Assets [Member]
Business Acquisition [Line Items]
Estimated average life in years	10 years
Finite-lived intangible assets acquired	$ 2.9
FNC, Inc. [Member] | Maximum [Member]
Business Acquisition [Line Items]
Consideration transferred	475.0
Certain closing adjustments to be paid	$ 75.0
PIQ Acquisition [Member]
Business Acquisition [Line Items]
Remaining equity interest acquired					40.00%	40.00%
Mandatorily redeemable noncontrolling interests					$ 19.0	NZD 27.8