Ownership Interests in and Advances to Partner Companies and Funds Unaudited Financial Information for Partner Companies and Funds (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2013 PixelOptics, Inc. [Member]	Dec. 31, 2012 PixelOptics, Inc. [Member]
Summary of Investments, Other than Investments in Related Parties, Reportable Data [Line Items]
Current assets	$ 221,001	$ 168,246	$ 285	$ 323
Non-current assets	90,042	74,555	4,588	5,259
Total assets	311,043	242,801	4,873	5,582
Current liabilities	153,398	125,491	56,721	34,184
Non-current liabilities	75,324	37,384	1,818	10,228
Shareholders’ equity	82,321	79,926	(53,666)	(38,830)
Total liabilities and shareholders’ equity	$ 311,043	$ 242,801	$ 4,873	$ 5,582