Related Party Transactions (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Fair value		$ 171,833		$ 171,833		$ 181,138
SP Corporate Services LLC
Provision of services		2,200	$ 2,200	6,800	$ 6,600
Accounts payable		100		100
Mutual Securities, Inc.
Paid commissions		77	73	106	295
iGo
Fixed annual fee	$ 400
WebBank | Interest Income
Interest income		8	$ 23	36	$ 65
WebBank | Short-term deposits
Short-term deposits		$ 3,300		$ 3,300
Steel Partners
Shares authorized		1,000,000		1,000,000
Common units (in shares)		442,337		442,337
Fair value		$ 7,300		$ 7,300
Steel Partners | Steel Excel
Ownership (as a percent)		58.20%		58.20%