Income per Share (Summary of Basic and Diluted Earnings per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income per Share
Net income available to common stockholders	$ 53,676	$ 31,738	$ 256,535	$ 127,607
Weighted average shares outstanding-basic (shares)	267,569,823	208,284,407	244,866,574	208,048,207
Potentially dilutive common shares:
Unvested incentive units (shares)	110,178	152,240	81,319	135,016
Unvested restricted stock	312,634		261,758
Forward equity offering (shares)	2,246,171	825,098	1,845,832	537,980
Market performance-based awards (shares)	505,602	173,827	520,531	173,091
Weighted average shares/units outstanding-diluted (shares/units)	270,744,408	209,435,572	247,576,014	208,894,294
Income per share:
Basic (in dollars per share)	$ 0.20	$ 0.15	$ 1.05	$ 0.61
Diluted (in dollars per share)	$ 0.20	$ 0.15	$ 1.04	$ 0.61