Investments in Partnerships - Summary of Equity Investments (Detail) - USD ($) $ in Thousands		Jun. 30, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Total assets		$ 796,202	$ 763,870
Investments in real estate, at cost:
Operating properties		565,907	612,689
Construction in progress		370,051	293,102
Total investments in real estate		935,958	905,791
Accumulated depreciation		(204,723)	(202,424)
Net investments in real estate		731,235	703,367
Cash and cash equivalents		33,017	26,158
Deferred costs and other assets, net		31,950	34,345
Total assets		796,202	763,870
LIABILITIES AND PARTNERS’ INVESTMENT:
Mortgage loans payable, net		510,820	513,139
Long Term Debt Equity Method Investment, net		247,645	0
Other liabilities		41,882	37,971
Total liabilities		800,347	551,110
Net investment		(4,145)	212,760
Partners’ share		(2,330)	106,886
PREIT’s share		(1,815)	105,874
Excess investment	[1]	14,121	13,081
Net investments and advances		12,306	118,955
Investment in partnerships, at equity		106,945	216,823
Distributions in excess of partnership investments		$ (94,639)	$ (97,868)

[1] Excess investment represents the unamortized difference between our investment and our share of the equity in the underlying net investment in the unconsolidated partnerships. The excess investment is amortized over the life of the properties, and the amortization is included in “Equity in income of partnerships.”