Business Acquisitions (Narrative) (Details) - USD ($) $ in Thousands												3 Months Ended	12 Months Ended
	Nov. 01, 2017	Oct. 01, 2017	Sep. 01, 2017	Jun. 01, 2017	Apr. 01, 2017	Nov. 02, 2016	Jul. 02, 2016	Jul. 01, 2016	Sep. 01, 2015	Jun. 01, 2015	Mar. 01, 2015	Jun. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Nov. 01, 2016	Dec. 02, 2014
Business Acquisition [Line Items]
Business Acquisition, Earnout Accrual Adjustment													$ 164	$ 1,344	$ 1,533
Derivative Liability													37,096	8,510	4,277
Payments to Acquire Business, Held in Escrow													4,040	0	0
Contingent liability for accrued earn-out acquisition consideration													33,096	6,589
Contingent liability for accrued earn-out acquisition consideration													4,000	1,921
Business acquisition, purchase price allocation, goodwill													666,863	441,404	402,259
Goodwill, Purchase Accounting Adjustments													12,158	(4,298)
Goodwill													666,863	441,404	402,259
Payments to Acquire Interest in Joint Venture													0	696	$ 6,000
Fair Value of Joint Venture, excluding Noncontrolling Interest					$ 120,000
Fair Value of Joint Venture, including Noncontrolling Interest					$ 150,000
Via
Business Acquisition [Line Items]
Derivative, Term of Contract	12 months
Business acquisition, cost of acquired entity, cash paid	$ 78,800
Via | Preliminary Allocation [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill	60,785
Goodwill	60,785
WDEV
Business Acquisition [Line Items]
Derivative Liability													$ 2,550
Derivative, Term of Contract						38 months							38 months
Payments to Acquire Business, Held in Escrow						$ 2,900								2,900
Business acquisition, cost of acquired entity, cash paid						10,500
WDEV | Final Allocation Adjustment [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill																$ (5,317)
Goodwill																(5,317)
WDEV | Preliminary Allocation [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill																13,615
Goodwill																13,615
Hope [Member]
Business Acquisition [Line Items]
Business acquisition, cost of acquired entity, cash paid						$ 1,720
Via Media Health
Business Acquisition [Line Items]
Derivative Liability													$ 0
Derivative, Term of Contract											24 months
Business acquisition, cost of acquired entity, cash paid											$ 1,000
Via Media Health | Customer relationships
Business Acquisition [Line Items]
Intangible Assets, Net (Excluding Goodwill)											383
Via Media Health | Technology
Business Acquisition [Line Items]
Intangible Assets, Net (Excluding Goodwill)											101
Via Media Health | Final Allocation
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill											2,000
Goodwill											2,000
PB Systems
Business Acquisition [Line Items]
Derivative Liability													0
Derivative, Term of Contract										24 months
Business acquisition, cost of acquired entity, cash paid										$ 12,400
PB Systems | Customer relationships
Business Acquisition [Line Items]
Intangible Assets, Net (Excluding Goodwill)												$ 2,100
PB Systems | Final Allocation
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill												11,200
Goodwill												11,200
PB Systems | Final Allocation Adjustment [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill										4,298
Finite-Lived Intangible Assets, Purchase Accounting Adjustments												(8,200)
Deferred Tax Liability, Purchase Accounting Adjustment												(3,200)
Increase (Decrease) in Derivative Liabilities												(664)
Goodwill, Purchase Accounting Adjustments												$ (4,300)
Goodwill										4,298
PB Systems | Preliminary Allocation [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill										6,800
Goodwill										6,800
PB Systems | Preliminary Allocation [Member] | Customer relationships
Business Acquisition [Line Items]
Intangible Assets, Net (Excluding Goodwill)										10,300
beBetter
Business Acquisition [Line Items]
Derivative, Term of Contract				24 months
Business acquisition, cost of acquired entity, cash paid				$ 1,000
beBetter | Preliminary Allocation [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill				447
Goodwill				447
ItzCash
Business Acquisition [Line Items]
Derivative Liability													34,550
Derivative, Term of Contract					36 months
Payments to Acquire Business, Held in Escrow					$ 4,000								4,000
Escrow Derivative, Term of Contract					12 months
Business acquisition, cost of acquired entity, cash paid					$ 76,300
ItzCash | Preliminary Allocation [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill					119,766
Goodwill					119,766
Oakstone | Final Allocation Adjustment [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill																	$ 948
Goodwill																	$ 948
PML [Member]
Business Acquisition [Line Items]
Business acquisition, cost of acquired entity, cash paid	37,400
Wall Street
Business Acquisition [Line Items]
Business acquisition, cost of acquired entity, cash paid		$ 7,400
Wall Street | Preliminary Allocation [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill		6,113
Goodwill		$ 6,113
YouFirst
Business Acquisition [Line Items]
Business acquisition, cost of acquired entity, cash paid			$ 10,200
YouFirst | Preliminary Allocation [Member]
Business Acquisition [Line Items]
Business acquisition, purchase price allocation, goodwill			7,395
Goodwill			$ 7,395
Minimum [Member] | Via Media Health
Business Acquisition [Line Items]
Derivative Liability											372
Maximum [Member] | WDEV
Business Acquisition [Line Items]
Derivative Liability																$ 15,700
Maximum [Member] | PB Systems
Business Acquisition [Line Items]
Derivative Liability										$ 8,000
Maximum [Member] | beBetter
Business Acquisition [Line Items]
Derivative Liability				$ 2,000
Maximum [Member] | ItzCash
Business Acquisition [Line Items]
Derivative Liability					$ 44,000
ItzCash
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage					80.00%
EbixHealth JV
Business Acquisition [Line Items]
Non-cash Payments To Acquire Interest In Joint Venture									$ 2,000
Equity Method Investment, Ownership Percentage Increase (Decrease)							11.00%	11.00%
Payments to Acquire Interest in Joint Venture							$ 2,000	$ 2,000	$ 6,000
Equity Method Investment, Ownership Percentage								51.00%	40.00%
Refund of Advance and withholding taxes [Member] | Via
Business Acquisition [Line Items]
Derivative Liability	2,000
Potential claims made by tax authorities [Member] | Via
Business Acquisition [Line Items]
Derivative Liability	$ 2,300
Performance Bonus [Member] | Via Media Health
Business Acquisition [Line Items]
Derivative Liability											$ 1,000
Contingent Accrued Earn-out Acquisition Consideration
Business Acquisition [Line Items]
Derivative Liability													$ 37,100	$ 8,500