Acquisitions of Ownership Interests in Partner Companies and Funds (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended	17 Months Ended	18 Months Ended	21 Months Ended	34 Months Ended	37 Months Ended	47 Months Ended	48 Months Ended	54 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	$ 17,073	$ 14,129
Hoopla Software, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments										$ 3,800
Convertible bridge loan	1,000
Novasom, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments											$ 21,000
Convertible bridge loan	500
Full Measure
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	4,000		$ 4,000
AppFirst, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments								$ 11,600
Convertible bridge loan	1,000
WebLinc
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	4,400			$ 6,600
Spongecell
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments									$ 14,000
Convertible bridge loan	2,000
InfoBionic
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	1,000					$ 9,500
Syapse, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	7,500				$ 5,800
Clutch Holdings, LLC
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments							$ 12,300
Convertible bridge loan	$ 2,000