Financing Activity - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Debt Instrument [Line Items]
Line of Credit Facility, Description			We have entered into four credit agreements (collectively, as amended, the “Credit Agreements”), as further discussed in our Annual Report on Form 10-K for the year ended December 31, 2015: (1) the 2013 Revolving Facility, (2) the 2014 7-Year Term Loan, (3) the 2014 5-Year Term Loan, and (4) the 2015 5-Year Term Loan. The 2014 7-Year Term Loan, the 2014 5-Year Term Loan and the 2015 5-Year Term Loan are collectively referred to as the “Term Loans.”
Term Loan Borrowing	$ 400,000,000		$ 400,000,000
Maximum Unsecured Borrowing Amount Under Unencumbered Debt Yield Covenant	201,600,000		201,600,000
Sales Per Square Foot			500
Long-term Debt	396,856,000		$ 396,856,000		$ 398,040,000
Line of Credit Facility, Commitment Fee Percentage			0.25%
Minimum [Member]
Debt Instrument [Line Items]
Capitalization Rates			6.50%
Maximum [Member]
Debt Instrument [Line Items]
Capitalization Rates			7.50%
2013 Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Letters of Credit Outstanding, Amount	7,400,000		$ 7,400,000
Interest Expense, Debt, Excluding Amortization	805,000	$ 649,600	2,277,400	$ 2,357,100
Non-cash amortization of deferred financing fees	198,700	209,800	596,200	1,181,300
Term Loans [Member]
Debt Instrument [Line Items]
Interest Expense, Debt, Excluding Amortization	3,125,000	2,707,000	9,161,900	5,935,700
Non-cash amortization of deferred financing fees	$ 190,900	$ 118,300	$ 431,500	$ 273,800
Seven Year Term Loan [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Description			On June 30, 2016, Pennsylvania Real Estate Investment Trust (“PREIT”), PREIT Associates, L.P. (“PREIT Associates”) and PREIT-RUBIN, Inc. (“PRI” and, collectively with PREIT and PREIT Associates, the “Borrower”) entered into an Amendment (the “Amendment”) to the 2014 7-Year Term Loan. The Amendment increased potential borrowing under the 2014 7-Year Term Loan from $100.0 million to $250.0 million, and expanded the accordion feature of the 2014 7-Year Term Loan from up to $200.0 million to up to $400.0 million. Among other things, the Amendment lowered the interest rates in the applicable pricing grid and extended the termination date from January 7, 2021 to December 29, 2021. Pursuant to the Amendment, amounts borrowed under the 2014 7-Year Term Loan bear interest at a rate between 1.35% and 1.90% per annum, depending on PREIT’s leverage, in excess of LIBOR, which is a reduction from the former range of 1.80% to 2.35%.