Issuances of Common Stock - At-the-Market (ATM) Program (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
At-the-Market (ATM) Program
Gross proceeds			$ 449,959	$ 94,076
ATM Program
At-the-Market (ATM) Program
At-the-Market equity distribution program, authorized shares (in shares)	33,402,405		33,402,405
Shares remaining for future issuance (in shares)	9,088,433		9,088,433
Common stock | ATM Program
At-the-Market (ATM) Program
Shares of common stock issued (in shares)	6,589,598	1,511,149	6,589,598	1,511,149
Gross proceeds	$ 454,800	$ 95,700	$ 454,800	$ 95,700