Acquisitions of Ownership Interests in Partner Companies and Funds (Detail) - USD ($) $ in Thousands	3 Months Ended		22 Months Ended	23 Months Ended	24 Months Ended	29 Months Ended	33 Months Ended	59 Months Ended	66 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	$ 4,476	$ 17,073
Equity method investments	132,298		$ 154,666	$ 154,666	$ 154,666	$ 154,666	$ 154,666	$ 154,666	$ 154,666
CloudMine
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	2,000		$ 5,500
InfoBionic
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments							$ 14,500
Convertible bridge loan	4,000
Lumesis, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments								$ 6,200
Convertible bridge loan	200
Novasom, Inc.
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments									$ 22,000
Convertible bridge loan	500
Full Measure
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	2,400				$ 8,600
Aventura
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments				$ 6,200
Equity method investments	0
Convertible bridge loan	300
WebLinc
Schedule of Equity Method Investments [Line Items]
Payments to acquire equity method investments	$ 1,000					$ 12,000