Investments (Detail) $ in Thousands	1 Months Ended			3 Months Ended		9 Months Ended
	Aug. 31, 2015 USD ($)	Jan. 31, 2015 USD ($) director shares	May. 31, 2014 USD ($) shares	Sep. 30, 2015 USD ($) shares	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) shares	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Aug. 31, 2013	Jan. 31, 2013
Fair value				$ 171,833		$ 171,833		$ 181,138
Gross Unrealized Losses				8,262		8,262		27,495
Sales of marketable securities				22,800	$ 9,400	39,446	$ 105,112
Impairment of marketable securities				(7,886)	0	(30,626)	0
Realized loss on financial instrument obligation				(1,300)	100	(1,100)	800
Loss on change to equity method at fair value				0	0	2,807	568
Value of investment				33,177		33,177		24,355
Cost-method investments				3,490		3,490		$ 28,525
Realized gain on non-monetary exchange				9,326	$ 0	9,326	$ 0
Venture Capital Funds
Other investments				500		500
Promissory Note
Other investments				$ 3,000		$ 3,000
Steel Partners
Common units (in shares) | shares				442,337		442,337
Fair value				$ 7,300		$ 7,300
Gross Unrealized Losses				$ 400		$ 400
Again Faster
Ownership (as a percent)				40.00%		40.00%		40.00%
Membership interest (as a percent)									44.70%	40.00%
Impairment charge				$ 2,500
API
Ownership (as a percent)			20.60%	20.60%		20.60%		20.60%
Number of shares held | shares			11,377,192
Number of shares purchased | shares			1,666,666
Loss on change to equity method at fair value			$ 600
Aviat Networks, Inc.
Ownership (as a percent)		12.90%		12.90%		12.90%
Number of shares held | shares		8,042,892
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)				45.70%		45.70%		46.90%
Value of investment				$ 4,100		$ 4,100
Partnership
Cost-method investments								$ 25,000
Realized gain on non-monetary exchange	$ 9,326
Value of shares received				$ 34,300		$ 34,300
Steel Partners | Steel Excel
Ownership (as a percent)				58.20%		58.20%