Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended		3 Months Ended	12 Months Ended		1 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	1 Months Ended	3 Months Ended	12 Months Ended	1 Months Ended	3 Months Ended	6 Months Ended	1 Months Ended
	Feb. 28, 2009 Parties	Sep. 30, 2003 Parties	Mar. 31, 2013 Cases	Mar. 31, 2013	Dec. 31, 2012	Oct. 31, 2012 Marketing Estate [Member]	Mar. 31, 2013 Marketing Estate [Member]	Mar. 31, 2013 Marketing Estate [Member]	Mar. 31, 2013 Marketing Estate [Member] Maximum [Member]	May 31, 2007 MTBE [Member] Defendant	Mar. 31, 2013 MTBE [Member] Parties	Dec. 31, 2010 MTBE [Member] Cases	Oct. 31, 2012 Litigation Funding Agreement [Member] Marketing Estate [Member]	Mar. 31, 2013 Litigation Funding Agreement [Member] Marketing Estate [Member]	Mar. 31, 2013 Litigation Funding Agreement [Member] Marketing Estate [Member]	Oct. 31, 2012 Litigation Funding Agreement [Member] Marketing Estate [Member] Lukoil Complaint [Member]
Commitments And Contingencies [Line Items]
Administrative claims							$ 10,500,000
Outstanding administrative claim							6,360,000	6,360,000
The amount received from the initial distribution in the Marketing liquidation							1,792,000
The aggregate amount received from the initial distribution in the Marketing liquidation								3,140,000
Maximum amount of loans to be made to the Marketing Estate per agreement						6,425,000							6,425,000
Interest rate per annum on funds advanced to the Marketing Estate for expert witnesses and wind down expenses													15.00%
Interest rate per annum on funds advanced for legal fees and expenses													15.00%
Percentage of gross proceeds from the Lukoil complaint																24.00%
Amount advanced to the Marketing Estate for wind down expenses							1,773,000							1,773,000
Aggregate amount advanced to the Marketing Estate for wind down expenses															3,445,000
Reimbursement of legal fees in connection with litigation funding agreement									1,300,000
Amount receivable related to amount advanced and reimbursable legal fees							4,745,000	4,745,000
Lease origination costs			325,000	3,472,000
Co-invest with tenants to fund capital improvements			14,080,000
Accrued legal matters			3,798,000	3,798,000	3,615,000
Number of potentially responsible parties for Lower Passaic River damages		66
Parties to perform a remedial investigation and feasibility study										70
Number of additional parties	300
Petroleum refiners, manufacturers, distributors and retailers											50
Agreements to settle												$ 1,725,000
Classes settled												2
Pending cases												52
Number of cases in which we remain a defendant			1