Equity - Shares and Units and Dividends (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Class of Stock [Line Items]
Percentage of dividends on common stock received until performance criteria met for LTIP units	10.00%		10.00%
Percentage of dividends on common stock received after performance criteria met for LTIP units	90.00%		90.00%
Percentage of dividends on common stock received in periods after performance criteria met for LTIP units	100.00%		100.00%
Net income attributable to common stockholders	$ 15,973	$ 11,220	$ 34,490	$ 25,478
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 non-controlling interests	$ 20,989	35,648	$ 54,707	78,491
Shares and Units [Abstract]
OP units outstanding (shares)	299,099,533		299,099,533
OP units owned by the Company (shares)	154,925,644		154,925,644
OP units owned by the Company, percent			51.80%
OP units not owned by the Company (shares)	144,173,889		144,173,889
OP units not owned by the Company, percent			48.20%
Dividends and Distributions [Abstract]
Dividends paid to common shareholders	$ 16,200	10,000	$ 39,500	29,000
Distributions paid to OP unitholders	15,100	12,800	43,100	39,200
Private perpetual preferred unit distributions	200	200	702	702
Additional Paid-In Capital
Class of Stock [Line Items]
Increase in additional paid-in capital for the conversion of OP Units into common stock	$ 5,016	$ 24,428	$ 20,217	$ 53,013