Investments (Detail) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended
	May. 31, 2014 USD ($) shares	Jan. 31, 2014 USD ($)	Jun. 30, 2015 USD ($) shares	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) shares	Jun. 30, 2014 USD ($)	Jan. 31, 2015 director shares	Dec. 31, 2014 USD ($)	Aug. 31, 2013	Jan. 31, 2013
Sales of marketable securities			$ 9,900	$ 55,200	$ 16,686	$ 95,740
Fair value			163,793		163,793			$ 181,138
Gross Unrealized Losses			(4,098)		(4,098)			(27,495)
Impairment of marketable securities			(22,740)	0	(22,740)	0
Realized loss on financial instrument obligation			(100)	(700)	(300)	(700)
Loss on change to equity method at fair value			0	$ 568	2,807	$ 568
Value of investment			38,834		38,834
Cost-method investments			3,467		3,467			$ 28,525
Venture Capital Funds
Other investments			500		500
Promissory Note
Other investments			$ 3,000		$ 3,000
Steel Partners
Common units (in shares) | shares			204,712		204,712
Fair value			$ 3,600		$ 3,600
Gross Unrealized Losses			$ (33)		$ (33)
Again Faster
Membership interest (as a percent)									44.70%	40.00%
Ownership (as a percent)			40.00%		40.00%			40.00%
API
Number of shares held | shares	11,377,192
Ownership (as a percent)	20.60%		20.60%		20.60%			20.60%
Number of shares purchased | shares	1,666,666
Loss on change to equity method at fair value	$ 600
Aviat Networks, Inc.
Number of shares held | shares							8,041,892
Ownership (as a percent)			12.90%		12.90%		12.90%
Loss on change to equity method at fair value		$ 2,800
Number of directors | director							2
Number of directors on board | director							8
iGo
Ownership (as a percent)			46.90%		46.90%			46.90%
Value of investment			$ 3,800		$ 3,800
Partnership
Cost-method investments			25,000		25,000
Fair value of cost method investments			$ 33,400		$ 33,400
Steel Partners | Steel Excel
Ownership (as a percent)			57.10%		57.10%