Equity - At-The-Market Offering (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	6 Months Ended
	Apr. 15, 2019	Mar. 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Mar. 04, 2019
ATM Program activity
Number of shares (in shares)	6,641,250
Gross proceeds	$ 149,000		$ 196,041	$ 47,547
Commissions paid on stock issuance		$ 600
At-The-Market Offering
Class of Stock [Line Items]
Remaining offering amount available			$ 300,000
ATM Program activity
Number of shares (in shares)		2,459,000
Average sales price per share (in usd per share)		$ 19.48
Gross proceeds		$ 47,893
At-The-Market Offering | Maximum
Class of Stock [Line Items]
Authorized aggregate offering price of common stock					$ 300,000