Investment in Affiliates, Net (Details) $ in Thousands, NZD in Millions, AUD in Millions	1 Months Ended				3 Months Ended									12 Months Ended
	Dec. 31, 2016 USD ($)	Nov. 30, 2016 USD ($)	Nov. 30, 2016 AUD	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jan. 31, 2016 USD ($)	Jan. 31, 2016 NZD	Dec. 31, 2015 NZD
Schedule of Investments [Line Items]
Acquisitions														$ 226,907	$ 119,589
Mandatorily redeemable noncontrolling interests	$ 0			$ 18,981	$ 0				$ 18,981					0	18,981
Investment in affiliates, net	40,809			69,205	40,809				69,205					40,809	69,205
Equity in earnings/(loss) of affiliates, net of tax					(99)	$ 607	$ 78	$ (90)	1,789	$ 3,498	$ 4,667	$ 3,766		496	13,720	$ 14,120
Income tax expense on earnings of investments in affiliates														1,000	9,100	8,900
Dividends received from investments in affiliates														9,044	30,084	38,655
Operating revenue					474,914	$ 523,896	$ 500,204	$ 453,543	390,886	$ 386,439	$ 386,013	$ 364,772		1,952,557	1,528,110	1,405,040
Operating expenses														1,677,968	1,325,186	1,235,282
Impairment Loss on Investment in affiliates														(23,431)	0	(360)
Gain (Loss) on Disposition of Assets														20,573	33,181	5,005
Goodwill	2,107,255			1,881,547	2,107,255				1,881,547					2,107,255	1,881,547	1,780,758
Other intangible assets, net	478,913			352,148	478,913				352,148					478,913	352,148
Business Combination, Acquisition Related Costs														6,900	3,900	9,000
Equity Method Investments [Member]
Schedule of Investments [Line Items]
Impairment Loss on Investment in affiliates	4,900
RELS LLC [Member]
Schedule of Investments [Line Items]
Business Acquisition, Goodwill, Expected Tax Deductible Amount				11,500					11,500						11,500
Gain on investments and other, net				34,300
Amount paid to acquire business				65,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment				27,000					27,000						27,000
PIQ Acquisition [Member]
Schedule of Investments [Line Items]
Mandatorily redeemable noncontrolling interests				$ 19,000					$ 19,000						19,000		$ 19,000	NZD 27.8	NZD 27.8
Remaining equity interest acquired																	40.00%	40.00%
Gain (Loss) on Disposition of Assets		$ 7,300	AUD 9.9
Onthehouse Acquisition [Member] [Member]
Schedule of Investments [Line Items]
Amount paid to acquire business		$ 8,300	AUD 11.3
Joint Venture Loan Originations Products and Services [Member]
Schedule of Investments [Line Items]
Operating revenue														10,300	18,200	19,000
Operating expenses														11,200	$ 13,000	$ 12,900
RELS LLC [Member]
Schedule of Investments [Line Items]
Remaining equity interest acquired				49.90%					49.90%						49.90%				49.90%
Ownership percentage in equity method investment				50.10%					50.10%						50.10%				50.10%
Percentage of income in equity earnings of affiliates, net of tax															84.90%	80.00%
Noncontrolling interest, ownership percentage by parent				100.00%					100.00%						100.00%				100.00%
STARS [Member]
Schedule of Investments [Line Items]
Investment in affiliates, net	2,990				$ 2,990									$ 2,990
Impairment Loss on Investment in affiliates	$ 18,500
Onthehouse Acquisition [Member] [Member]
Schedule of Investments [Line Items]
Percentage of income in equity earnings of affiliates, net of tax		12.97%	12.97%
Symbility [Member]
Schedule of Investments [Line Items]
Investment in affiliates, net													$ 18,300
Ownership percentage in equity method investment													29.40%
Difference between the purchase price and interest in the net assets													$ 11,300
Goodwill													2,000
Other intangible assets, net													$ 9,400
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life													15 years