Business Acquisitions (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) Business	Dec. 31, 2014 USD ($) Business	Dec. 31, 2013 USD ($) Business
Business Acquisition [Line Items]
Number of business acquired | Business	8	3	2
Fair value of assets acquired and liabilities assumed [Abstract]
Intangible Assets Other than Goodwill			$ 493,000
Goodwill	$ 5,824,726	$ 4,710,691	4,549,998
Intangibles acquired			493,000
Finite lived intangible assets			$ 465,000
Weighted average useful life			19 years
Cost of acquired entity transaction costs			$ 3,300
Trade Names [Member]
Fair value of assets acquired and liabilities assumed [Abstract]
Indefinite lived intangible assets			28,000
Customer Relationships [Member]
Fair value of assets acquired and liabilities assumed [Abstract]
Finite lived intangible assets			$ 451,000
Weighted average useful life			20 years
Technology [Member]
Fair value of assets acquired and liabilities assumed [Abstract]
Finite lived intangible assets			$ 12,000
Weighted average useful life			7 years
Noncompete Agreements [Member]
Fair value of assets acquired and liabilities assumed [Abstract]
Finite lived intangible assets			$ 2,000
Weighted average useful life			5 years
Immaterial Acquisitions [Member]
Business Acquisition [Line Items]
Cost of acquired entity purchase price	1,800,000	303,000
Fair value of assets acquired and liabilities assumed [Abstract]
Intangible Assets Other than Goodwill	731,000	99,000
Goodwill	1,200,000	208,000
Indefinite lived intangible assets	51,000	7,000
Intangibles acquired	731,000	99,000
Finite lived intangible assets	$ 680,000	$ 92,000
Weighted average useful life	17 years	17 years
Cost of acquired entity transaction costs	$ 5,900	$ 2,800
Immaterial Acquisitions [Member] | Backlog [Member]
Fair value of assets acquired and liabilities assumed [Abstract]
Finite lived intangible assets		$ 1,000
Weighted average useful life		1 year
Immaterial Acquisitions [Member] | Customer Relationships [Member]
Fair value of assets acquired and liabilities assumed [Abstract]
Finite lived intangible assets	$ 541,000	$ 82,000
Weighted average useful life	19 years	19 years
Immaterial Acquisitions [Member] | Technology [Member]
Fair value of assets acquired and liabilities assumed [Abstract]
Finite lived intangible assets	$ 100,000	$ 7,000
Weighted average useful life	8 years	6 years
Immaterial Acquisitions [Member] | Software [Member]
Fair value of assets acquired and liabilities assumed [Abstract]
Finite lived intangible assets	$ 39,000	$ 2,000
Weighted average useful life	6 years	4 years
Advanced Sensors, Ltd [Member]
Business Acquisition [Line Items]
Cost of acquired entity purchase price			$ 54,000
Fair value of assets acquired and liabilities assumed [Abstract]
Goodwill			28,000
Indefinite lived intangible assets			28,000
Managed Health Care Associates, Inc [Member]
Business Acquisition [Line Items]
Cost of acquired entity purchase price			1,000,000
Fair value of assets acquired and liabilities assumed [Abstract]
Current assets			59,813
Intangible Assets Other than Goodwill			465,500
Goodwill			678,183
Other assets			5,798
Total assets acquired			1,209,294
Current liabilities			(24,717)
Long-term deferred tax liability			(162,503)
Other liabilities			(6,524)
Net assets acquired			1,015,550
Fair value adjustment for admin fees related to customer purchases			35,000
Fair value liability related revenue-share obligation			8,600
Intangibles acquired			$ 465,500