Issuances of Common Stock - At-the-Market (ATM) Program (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
At-the-Market (ATM) Program
Gross proceeds			$ 1,471,595	$ 442,157
ATM Program
At-the-Market (ATM) Program
At-the-Market equity distribution program, authorized shares (in shares)	69,088,433		69,088,433
Shares remaining for future issuance (in shares)	54,299,611		54,299,611
Common stock | ATM Program
At-the-Market (ATM) Program
Shares of common stock issued (in shares)	14,788,822	5,536,619	21,378,420	7,047,768
Gross proceeds	$ 1,032,300	$ 346,500	$ 1,487,100	$ 442,200