Equity - Additional Information (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) $ / shares shares	Mar. 31, 2015 USD ($) shares	Dec. 31, 2015 USD ($)	Jul. 31, 2015 shares
Equity [Line Items]
Proceeds from issuance of common shares | $	$ 3,751	$ 6,582
Authorized amount (in shares)				10,000,000
Treasury stock acquired (in shares)	1,184,113
Treasury stock acquired, average cost (in dollars per share) | $ / shares	$ 7.56
Gains and losses on cash flow hedges | $	$ (6,564)		$ (1,939)
OP unit equivalent in common shares	1.13
Partners' capital account, units	3,393,000
Direct Share Purchase Plan [Member]
Equity [Line Items]
Common shares issued during period	577,823	627,247
Proceeds from issuance of common shares | $	$ 4,115	$ 6,685