Equity - At-The-Market Offering (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Apr. 15, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Mar. 04, 2019
ATM Program Activity
Number of shares (shares)	6,641,250
Gross proceeds	$ 149,000	$ 195,924	$ 179,882	$ 170,323
ATM Program
Class of Stock [Line Items]
Remaining offering amount available		$ 300,000
ATM Program | Maximum
Class of Stock [Line Items]
Authorized aggregate offering price of common stock					$ 300,000
Prior ATM Program
ATM Program Activity
Number of shares (shares)		2,459,000	10,265,000
Average sales price per share (usd per share)		$ 19.48	$ 17.76
Gross proceeds		$ 47,893	$ 182,321
Commissions paid on stock issuance		$ 600	$ 2,300