Fair Value Measurements and Investments - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands					3 Months Ended				9 Months Ended
		Sep. 08, 2016	Jun. 02, 2016	Jun. 01, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Goodwill					$ 1,882,244				$ 1,882,244		$ 1,222,601
Common stock, shares issued					267,868,000				267,868,000		266,545,000
Carrying values of equity method investment	[1]				$ 2,436				$ 2,436		$ 205,553
Closing price of fair value investment					197,250				197,250		0
Unrealized loss of fair value investment					10,316			$ (1,619)	(7,869)	$ (2,010)
Asset impairment charges					0		$ 4,650	$ 22	4,650	341
Total consideration for non-marketable convertible note of a third party							500
Total consideration for non marketable equity securities						$ 10,200			20,685	$ 212,654
Carrying values of cost method investments					$ 26,041				$ 26,041		$ 17,876
1.25% Cash Convertible Senior Notes [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Interest rate					1.25%				1.25%
Other Assets [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Convertible note fair value					$ 500				$ 500
Carrying values of cost method investments					10,200				$ 10,200
Cost Method Equity Investments
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Asset impairment charges							$ 2,100
NantHealth, Inc [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Common Stock shares voting percent			12.40%						12.40%
Aggregate voting interest on common stock			15,000,000
Carrying values of equity method investment					205,600				$ 205,600
NantHealth, Inc [Member] | IPO [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Common stock, shares issued			6,500,000	14,285,714
Common Stock shares voting percent			11.80%	12.60%
Additional shares purchased			714,286
Additional shares purchased per share			$ 14
Additional shares purchased investment amount			$ 10,000
NantHealth Common Stock [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Closing price of fair value investment					$ 197,300				197,300
Unrealized loss of fair value investment									$ 8,400
Third Party
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Majority interest acquired in a third party		$ 29,000
Goodwill		45,200
Intangible assets		21,400
Estimated fair value of non controlling interest		$ 29,400

[1] Allscripts share of the earnings of our equity method investees is reported based on a one quarter lag.