Investments in Unconsolidated Joint Ventures - Balance Sheet Footnotes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Investments in unconsolidated joint ventures:
Total assets	$ 9,771,749		$ 9,791,249
Amortization of difference between cost of investments and book value of underlying equity	4,027	$ 4,457
Northwestern Mutual Life (NML)
Investments in unconsolidated joint ventures:
Mortgage notes payable to affiliate	489,206		265,863
Interest expense on borrowings from related party	3,160	$ 6,366
Pacific Premier Retail LLC
Investments in unconsolidated joint ventures:
Total assets	3,177,394		3,179,255
Total liabilities	$ 1,892,163		$ 1,887,952