Consolidated Statements of Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Stockholders' Equity [Abstract]
Issuance of shares, offering costs	$ 2,042	$ 7,153	$ 10,388
Common shares, dividend declared per share (in dollars per share)	$ 1.28	$ 0.93	$ 0.84
LTIP units, distributions per unit (in dollars per share)	$ 1.28	$ 0.93	$ 0.84