Business Combinations (Narrative) (Details) $ in Thousands								3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 01, 2017 USD ($)	Jun. 01, 2017 USD ($)	Apr. 01, 2017 USD ($)	Nov. 02, 2016 USD ($)	Jul. 02, 2016 USD ($)	Sep. 02, 2015 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) Companies	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) Companies	Nov. 01, 2016 USD ($)	Jul. 01, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 01, 2015
Business Acquisition [Line Items]
Recognized controlling ownership of joint venture										$ 27,586
Non-operating income, gain on joint venture investment (see Note 8)								$ 0	$ 1,162	$ 0	$ 1,162	$ 1,162
Number of Businesses Acquired | Companies										3		3
Reduction of acquisition earnout accruals										$ (164)	(1,726)
Goodwill, Translation and Purchase Accounting Adjustments	[1]									(3,432)	(664)	$ (664)
Derivative Liability								39,179		39,179		8,510			$ 4,277
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability								164		3,596	$ 2,390
Goodwill, Purchase Accounting Adjustments										(11,342)		4,298
Business acquisition, contingent consideration, at fair value, noncurrent								33,258		33,258		6,589
Business acquisition, contingent consideration, at fair value, current								5,921		5,921		1,921
Goodwill								559,163		559,163		441,404			$ 402,259
Fair Value of Joint Venture, excluding Noncontrolling Interest				$ 120,000
Fair Value of Joint Venture, including Noncontrolling Interest				150,000
WSFIN [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		$ 7,300
PML [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		36,600
YouFirst [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		$ 8,000
beBetter [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross			$ 1,000
Derivative, Term of Contract			24 months
ItzCash [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross				$ 76,300
Derivative, Term of Contract				36 months
Payments to Acquire Business, Held in Escrow				$ 4,000
Escrow Derivative, Term of Contract				12 months
WDEV [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross					$ 10,500
Derivative, Term of Contract					38 months
Payments to Acquire Business, Held in Escrow					$ 2,900
Escrow Derivative, Term of Contract					38 months
Hope [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross					$ 1,720
Maximum [Member] | beBetter [Member]
Business Acquisition [Line Items]
Derivative Liability			$ 2,000
Maximum [Member] | ItzCash [Member]
Business Acquisition [Line Items]
Derivative Liability				$ 44,000
Maximum [Member] | WDEV [Member]
Business Acquisition [Line Items]
Derivative Liability													$ 15,700
Contingent accrued earn-out acquisition consideration [Member]
Business Acquisition [Line Items]
Derivative Liability								39,179		39,179		8,510
Business acquisition, contingent consideration, at fair value, noncurrent								33,300		33,300		6,600
Business acquisition, contingent consideration, at fair value, current								$ 5,900		5,900		$ 1,900
ItzCash [Member]
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage				80.00%
EbixHealth JV [Member]
Business Acquisition [Line Items]
Recognized controlling ownership of joint venture										$ 11,293
Goodwill														$ 13,161
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill														$ 9,071
Equity Method Investment, Ownership Percentage Increase (Decrease)						11.00%
Payments to Acquire Interest in Joint Venture						$ 2,000	$ 6,000
Equity Method Investment, Ownership Percentage														51.00%		40.00%

[1] Recorded as an adjustment to reported general and administrative expenses