Nature of the Business and Basis of Presentation (Details) - USD ($)		1 Months Ended		2 Months Ended	6 Months Ended
	Aug. 10, 2020	Feb. 29, 2020	Jan. 31, 2020	Feb. 29, 2020	Jun. 30, 2020	Jun. 30, 2019
Nature of business [Line Items]
Proceeds from issuance of common shares				$ 282,833,000	$ 283,333,000	$ 282,000,000
Other offering expenses					$ 500,000	$ 517,000
Sixth Street Financing Agreement | Senior secured debt | Subsequent Event
Nature of business [Line Items]
Credit agreement term	5 years
Credit facility capacity	$ 500,000,000
2020 RPI Funding Agreement | Subsequent Event
Nature of business [Line Items]
Sales-based participation rights sold, value	250,000,000
Public Offering
Nature of business [Line Items]
Common stock issued (shares)			4,830,917
Fair value of common share			$ 51.75
Proceeds from issuance of common shares			$ 245,877,000
Underwriting discounts and commissions			3,623,000
Other offering expenses			$ 500,000
Over-Allotment Option
Nature of business [Line Items]
Common stock issued (shares)		724,637
Proceeds from issuance of common shares		$ 36,956,000
Underwriting discounts and commissions		$ 543,000
RPI Preferred Share Purchase Agreement | Series B Preferred Shares | Subsequent Event
Nature of business [Line Items]
Total consideration on sale of shares	$ 200,000,000