Equity - Shares and Units and Dividends (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Class of Stock [Line Items]
Percentage of dividends on common stock received until performance criteria met for LTIP units	10.00%
Percentage of dividends on common stock received after performance criteria met for LTIP units	90.00%
Net income attributable to common stockholders	$ 7,428	$ 3,138
Increase in additional paid-in capital for the conversion of OP Units into common stock	0
Change from net income attributable to common stockholders and transfers from noncontrolling interests	$ 14,286	22,631
Shares and Units [Abstract]
OP units outstanding (shares)	269,438,815
OP units owned by the Company (shares)	121,746,700
OP units owned by the Company, percent	45.20%
OP units not owned by the Company (shares)	147,692,115
OP units not owned by the Company, percent	54.80%
Dividends and Distributions [Abstract]
Dividends paid to common shareholders	$ 10,300	9,400
Distributions paid to OP unitholders	12,600	13,300
Private perpetual preferred unit distributions	234	234
Additional Paid-In Capital
Class of Stock [Line Items]
Increase in additional paid-in capital for the conversion of OP Units into common stock	$ 6,858	$ 19,493