Acquisitions (Details) $ in Thousands, NZD in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jan. 31, 2016 USD ($)	Jan. 31, 2016 NZD
Business Acquisition [Line Items]
Goodwill, Purchase Accounting Adjustments				$ (5,681)
Acquisition-related costs		$ 7,300	$ 5,100	7,500	$ 6,100
Property Intelligence [Member]
Business Acquisition [Line Items]
Goodwill, Purchase Accounting Adjustments				(5,681)
FNC, Inc. [Member]
Business Acquisition [Line Items]
Cash paid at closing in acquisition	$ 400,000
Contingent consideration	8,000
Deferred tax liability acquired	85,400
FNC, Inc. [Member] | Property Intelligence [Member]
Business Acquisition [Line Items]
Goodwill, Acquired During Period	220,200
Goodwill, Purchase Accounting Adjustments				$ 5,400
FNC, Inc. [Member] | Property and equipment [Member]
Business Acquisition [Line Items]
Property and equipment acquired	$ 79,800
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	$ 145,300
FNC, Inc. [Member] | Trade names [Member]
Business Acquisition [Line Items]
Estimated average life in years	19 years
Finite-lived intangible assets acquired	$ 15,900
FNC, Inc. [Member] | Non-compete agreements [Member]
Business Acquisition [Line Items]
Estimated average life in years	5 years
Finite-lived intangible assets acquired	$ 18,800
FNC, Inc. [Member] | Maximum [Member]
Business Acquisition [Line Items]
Consideration transferred	475,000
Certain closing adjustments to be paid	$ 75,000
PIQ Acquisition [Member]
Business Acquisition [Line Items]
Remaining equity interest acquired						40.00%	40.00%
Mandatorily redeemable noncontrolling interests						$ 19,000	NZD 27.8