Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended	12 Months Ended
	May 15, 2020	Jun. 12, 2019	Jun. 10, 2019	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Subsidiary, Sale of Stock [Line Items]
Proceeds from issuance of common stock, net of issuance costs	$ 311,300				$ 311,321	$ 195,289	$ 0
Underwriting discounts, commissions and offering costs	$ 12,700				$ 8,200
Public Stock Offering
Subsidiary, Sale of Stock [Line Items]
Issuance of common stock from registered public offering (in shares)	4,735,294	395,698	2,637,986
Issuance of common stock from registered public offering (in usd per share)	$ 76.50		$ 69.50
Public Stock Offering - Shares From Parent
Subsidiary, Sale of Stock [Line Items]
Issuance of common stock from registered public offering (in shares)	4,235,294		2,913,684
Issuance of common stock from registered public offering (in usd per share)		$ 69.50
Public Stock Offering - Shares From Existing Shareholders
Subsidiary, Sale of Stock [Line Items]
Issuance of common stock from registered public offering (in shares)	500,000	120,000
Proceeds from issuance of common stock, net of issuance costs				$ 195,300