Issuances of Common Stock - Issuance of Common Stock in an Overnight Offering (Details) - USD ($) $ in Thousands	1 Months Ended		12 Months Ended
	May 31, 2019	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Issuance of Common Stock
Proceeds from shares issuances, net			$ 845,061	$ 0	$ 704,938
Overnight Offering | Common stock
Issuance of Common Stock
Shares of common stock issued (in shares)	12,650,000	11,850,000		0
Underwriting discounts and other offering costs	$ 31,000	$ 29,800
Proceeds from shares issuances, net	$ 845,100	$ 704,900