Organization, Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Operating Partnership's Equity Interest (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Variable Interest Entity [Line Items]
Payments to noncontrolling interests	$ 105,994	$ 84,610	$ 221,330
Fund I and Mervyns I [Member]
Variable Interest Entity [Line Items]
Operating partnership share of capital	22.22%
Fund Size	$ 90,000
Capital called	86,600
Unfunded Commitment	$ 0
Equity Interest Held By Operating Partnership	37.78%
Preferred Return	9.00%
Total distributions	$ 194,500
Fund II and Mervyns II [Member]
Variable Interest Entity [Line Items]
Operating partnership share of capital	28.33%
Fund Size	$ 300,000
Capital called	347,100
Unfunded Commitment	$ 0
Equity Interest Held By Operating Partnership	28.33%
Preferred Return	8.00%
Total distributions	$ 131,600
Fund III [Member]
Variable Interest Entity [Line Items]
Operating partnership share of capital	24.54%
Fund Size	$ 502,500
Capital called	387,500
Unfunded Commitment	$ 62,500
Equity Interest Held By Operating Partnership	39.63%	24.54%
Preferred Return	6.00%
Total distributions	$ 445,700
Additional ownership interest acquired		4.60%
Payments to noncontrolling interests		$ 7,300
Fund IV [Member]
Variable Interest Entity [Line Items]
Operating partnership share of capital	23.12%
Fund Size	$ 540,600
Capital called	179,400
Unfunded Commitment	$ 361,200
Equity Interest Held By Operating Partnership	23.12%
Preferred Return	6.00%
Total distributions	$ 101,900
Fund V [Member]
Variable Interest Entity [Line Items]
Operating partnership share of capital	20.10%
Fund Size	$ 520,100
Capital called	0
Unfunded Commitment	$ 520,100
Equity Interest Held By Operating Partnership	20.10%
Preferred Return	6.00%
Total distributions	$ 0
Fund II [Member]
Variable Interest Entity [Line Items]
Equity Interest Held By Operating Partnership	28.33%
Total distributions				$ 47,100
Additional ownership interest acquired	8.30%
Payments to noncontrolling interests	$ 18,400