Description of Trust and Reporting Policies - Additional Information (Detail) (USD $)	1 Months Ended
	Jan. 31, 2015	Dec. 31, 2014
Liquidation Basis of Accounting [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Accrued dividends and interest income		$ 3,600,000
Accrued dividends		3,465,000
Accrued interest income		$ 94,000
Subsequent Event [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Dividends declared per share for accrued dividend	$ 0.30
Accrued dividends record date	Mar. 11, 2015