Consolidated Statements of Equity (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Consolidated Statements of Equity
Exchange of limited partner units, units (in shares)		7,447,921
Exchange of limited partner units, common shares	596,051	6,795,296	584,432
Public offering of common stock, shares		9,137,500
Stock options exercised, common shares	1,567	712	324,720
Stock options exercised related to fund required withholding tax, shares			76,969
Common Stock Retired, shares			61,584
Stock incentive program, shares, net	107,123	114,066	116,885
Issuance of unit equivalents and other, treasury stock, shares			6,857
Net income attributable to preferred interests in the Operating Partnership (in dollars)	$ 1,915	$ 1,915	$ 1,915
Net income attributable to noncontrolling redeemable interests in properties in temporary equity (in dollars)	$ 8,858	$ 8,520	$ 8,946