Equity (Details) $ / shares in Units, shares in Thousands, $ in Thousands				1 Months Ended		12 Months Ended
	Mar. 02, 2017 $ / shares	Feb. 02, 2017 $ / shares	Oct. 07, 2015 USD ($) property	Oct. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2016 USD ($) item $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 $ / shares shares
Equity
Dividends declared per common share (in dollars per share) | $ / shares		$ 0.37				$ 2.095	$ 2.26	$ 2.18
Dividends paid per common share | $ / shares						$ 2.095	$ 2.26	$ 2.18
Maximum sales under equity offering program					$ 750,000
Common stock issued (in shares) | shares							1,800
Weighted average price (in dollars per share) | $ / shares							$ 40.14
Proceeds from issuance of common stock							$ 73,000
Stock issuance fees and commissions							1,000
Accumulated Other Comprehensive Loss
Cumulative foreign currency translation adjustment						$ (22,817)	(19,485)
Unrealized losses on cash flow hedges, net						(3,642)	(7,582)
Supplemental Executive Retirement Plan minimum liability						(3,129)	(3,411)
Unrealized (losses) gains on available for sale securities						(54)	8
Total accumulated other comprehensive loss						$ (29,642)	(30,470)
Noncontrolling interests
Number of Down REIT units | item						4,000,000
DownREIT unit, carrying value						$ 179,336	$ 185,608
HCP Ventures V
Noncontrolling interests
Number of Real Estate Properties | property			11
Subsequent event
Equity
Dividends paid per common share | $ / shares	$ 0.37
HCP Ventures V
Noncontrolling interests
Noncontrolling interest (as a percent)			49.00%	49.00%
Noncontrolling Interest, Increase from Sale of Parent Equity Interest			$ 110,000	$ 110,000
Consideration received from sale of noncontrolling interest in HCP Ventures V			$ 110,000	$ 110,000
Common Stock
Equity
Common stock issued (in shares) | shares						2,552	5,117	2,939
Company's common stock issuances
Dividend Reinvestment and Stock Purchase Plan (in shares) | shares						2,021	2,762	2,299
Conversion of DownREIT units (in shares) | shares						145	104	27
Exercise of stock options (in shares) | shares						133	823	169
Vesting of restricted stock units (in shares) | shares						529	409	614
Repurchase of common stock (in shares) | shares						237	198	323
Total Noncontrolling Interests
Company's common stock issuances
Conversion of DownREIT units (in shares) | shares						7,000
Noncontrolling interests
Non-managing members DownREIT units outstanding | item						4,000,000
Number of DownREIT LLCs | item						5
DownREIT unit, carrying value						$ 179,000
DownREIT unit, fair value						$ 199,000