Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary of Unaudited Quarterly Results of Operations
Revenues as reported and adjusted											$ 3,859,826	$ 3,343,546	$ 2,880,608
Net income (loss) attributable to common stockholders	$ 132,929	[1]	$ 182,043	[2]	$ 312,573	$ 190,799	$ 188,639	$ 136,255	$ 71,829	$ 50,022	$ 818,344	$ 446,745	$ 78,714
Net income (loss) attributable to common stockholders per share:
Basic	$ 0.38	[1]	$ 0.52	[2]	$ 0.89	$ 0.57	$ 0.58	$ 0.44	$ 0.24	$ 0.17	$ 2.35	$ 1.46	$ 0.28
Diluted	$ 0.37	[1]	$ 0.52	[2]	$ 0.89	$ 0.56	$ 0.57	$ 0.44	$ 0.24	$ 0.17	$ 2.34	$ 1.45	$ 0.28
Quarterly Results of Operations (Textuals) [Abstract]
Decreases in net income amounts and per share attributable to gains on sales of real estate			$ 2,046		$ 190,111
Temporary impairment charge and transaction cost	$ 35,648
Scenario, Previously Reported [Member]
Summary of Unaudited Quarterly Results of Operations
Revenues as reported and adjusted	$ 1,029,484	[1]	$ 978,997	[2]	$ 957,169	$ 894,177	$ 867,770	$ 847,523	$ 826,446	$ 801,807

[1] The decrease in net income and amounts per share are primarily attributable to the other than temporary impairment charge of $35,648,000 recognized on the available-for-sale investment and increased transaction costs incurred due to fourth quarter acquisitions.

[2] The decrease in net income and amounts per share are primarily attributable to gains on sales of real estate of $190,111,000 for the second quarter as compared to gains of $2,046,000 for the third quarter.