Ownership Interests in and Advances to Partner Companies and Funds - Summary of the carrying value of the Company's ownership interests in and advances to partner companies and private equity funds (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Investments in and Advances to Affiliates [Line Items]
Equity method investments	$ 151,840	$ 135,989
Cost method investments	6,990	9,138
Advances to partner companies	12,771	9,065
Total	171,601	154,192
Partner companies [Member]
Investments in and Advances to Affiliates [Line Items]
Equity method investments	150,898	134,861
Cost method investments	5,024	6,774
Private equity funds [Member]
Investments in and Advances to Affiliates [Line Items]
Equity method investments	942	1,128
Cost method investments	$ 1,966	$ 2,364