Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash flows from operating activities:
Net income	$ 179,447	$ 119,592
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	86,847	61,980
Amortization of deferred financing costs	5,617	3,328
Non-cash interest expense related to amortization of discount on equity component of exchangeable senior notes	2,473	1,393
Non-cash interest expense related to amortization of premium on notes payable	(696)	(1,682)
Compensation expense related to stock-based awards	4,093	2,795
Gain on sale of real estate assets and purchase of joint venture partners' interests	(26,923)	(2,857)
Gain on real estate transactions and earnout from prior acquisition	(9,814)	(400)
Distributions from unconsolidated real estate ventures in excess of earnings	1,936	3,459
Changes in operating assets and liabilities:
Receivables from related parties and affiliated real estate joint ventures	1,720	(1,302)
Other assets	(1,186)	(2,961)
Accounts payable and accrued expenses	(402)	3,857
Other liabilities	(3,442)	(3,915)
Net cash provided by operating activities	239,670	183,287
Cash flows from investing activities:
Acquisition of real estate assets	(435,298)	(240,892)
Development and redevelopment of real estate assets	(14,400)	(9,926)
Proceeds from sale of real estate assets	17,582	800
Change in restricted cash	15,506	(179)
Investment in unconsolidated real estate ventures	(19,309)	0
Return of investment in unconsolidated real estate ventures	1,318	0
Purchase/issuance of notes receivable	(10,656)	0
Principal payments received from notes receivable	41,393	0
Purchase of equipment and fixtures	(2,128)	(2,592)
Net cash used in investing activities	(405,992)	(252,789)
Cash flows from financing activities:
Proceeds from the sale of common stock, net of offering costs	73,369	416,643
Repurchase of exchangeable senior notes	(22,192)	0
Proceeds from notes payable and lines of credit	492,880	892,140
Principal payments on notes payable and lines of credit	(222,923)	(973,656)
Deferred financing costs	(5,702)	(3,451)
Net proceeds from exercise of stock options	313	1,102
Proceeds from termination of interest rate cap	1,650	0
Dividends paid on common stock	(171,514)	(123,473)
Distributions to noncontrolling interests	(14,300)	(11,573)
Net cash provided by financing activities	131,581	197,732
Net decrease in cash and cash equivalents	(34,741)	128,230
Cash and cash equivalents, beginning of the period	75,799	47,663
Cash and cash equivalents, end of the period	41,058	175,893
Supplemental schedule of cash flow information
Interest paid	59,676	40,984
Income taxes paid	8,516	1,431
Redemption of Operating Partnership units held by noncontrolling interests for common stock:
Noncontrolling interests in Operating Partnership	(829)	(138)
Common stock and paid-in capital	829	138
Tax effect from vesting of restricted stock grants and option exercises
Other assets	1,267	(1,242)
Paid-in capital	(1,267)	1,242
Acquisitions of real estate assets
Real estate assets, net	65,960	122,132
Operating Partnership units issued	(56,237)	(106,522)
Notes payable assumed	(9,723)	0
Receivables from related parties and affiliated real estate joint ventures	0	(15,610)
Accrued construction costs and capital expenditures
Acquisition of real estate assets	7,567	0
Development and redevelopment of real estate assets	1,298	0
Accounts payable and accrued expenses	(8,865)	0
Distribution of real estate from investments in unconsolidated real estate ventures
Real estate assets, net	17,261	0
Investments in unconsolidated real estate ventures	(17,261)	0
Disposition of real estate assets
Real estate assets, net	(7,689)	0
Redemption of Operating Partnership Units [Member]
Disposition of real estate assets
Operating Partnership units redeemed	$ 7,689	$ 0