Common Stock and Other Equity Related Transactions - Common Stock, OP Units, and Distributions (Details) - shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Common Stock Outstanding [Roll Forward]
Shares outstanding at January 1, (shares)	179,842,036	177,170,320	171,058,772
Common stock issued through the At-The-Market Offering Program (in shares)	1,010,472	1,722,282	2,760,034
Common stock issued through conversion of OP Units (in shares)	997,750	176,268	2,671,800
Common stock issued through exercise of options (in shares)	5,600	405,600	440,000
Common stock issued through restricted stock grants (in shares)	193,262	385,010	260,852
Common stock forfeitures (in shares)	0	0	(1,980)
Common stock issued through ESPP and Dividend Reinvestment Plan (in shares)	41,589	45,144	50,202
Common stock repurchased and retired (in shares)	(1,114)	(62,588)	(69,360)
Shares outstanding at December 31, (shares)	182,089,595	179,842,036	177,170,320