Investments in Partnerships - Summary of Equity Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Investments in real estate, at cost:
Operating properties	$ 739,199	$ 575,149
Construction in progress	362,928	420,771
Total investments in real estate	1,102,127	995,920
Accumulated depreciation	(223,790)	(212,574)
Net investments in real estate	878,337	783,346
Cash and cash equivalents	33,895	20,446
Deferred costs and other assets, net	41,441	30,549
Total assets	953,673	834,341
LIABILITIES AND PARTNERS’ INVESTMENT:
Mortgage loans payable, net	501,095	507,090
FDP Term Loan, net	298,960	247,901
Other liabilities	82,450	34,463
Total liabilities	882,505	789,454
Net investment	71,168	44,887
Partners’ share	33,661	21,583
PREIT’s share	37,507	23,304
Excess investment	18,379	15,763
Net investments and advances	55,886	39,067
Reconciliation to comparable GAAP balance sheet item:
Investment in partnerships, at equity	143,440	131,124
Distributions in excess of partnership investments	(87,554)	(92,057)
Net investment	$ 55,886	$ 39,067