Long-Term Debt - Credit Facility (Details) - USD ($)				3 Months Ended
	Mar. 16, 2020	Feb. 26, 2020	Nov. 28, 2018	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Details for the Credit Facility
Long-term debt				$ 952,756,000		$ 589,294,000
Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum revolving credit	$ 465,000,000.0	$ 425,000,000.0	$ 250,000,000.0
Long-term debt term			3 years
Details for the Credit Facility
Credit Facility principal balance				415,000,000		50,000,000
Less: Debt issue cost				3,213,000		1,083,000
Long-term debt				$ 411,787,000		$ 48,917,000
Stated interest rate				2.53%	4.49%
Interest Expense and Amortization of Debt Issue Costs
Interest expense				$ 1,360,000	$ 112,000
Unused facility fee				109,000	180,000
Debt issue cost amortization				186,000	141,000
Interest Expense				$ 1,655,000	$ 433,000
LIBOR | Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate	1.75%	1.75%
Interest Rate Option One | LIBOR | Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate			2.00%
Interest Rate Option Two | Federal Funds Rate | Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.50%
Interest Rate Option Two | LIBOR | Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.00%
Minimum | Interest Rate Option One | LIBOR | Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate			0.25%
Maximum | Interest Rate Option One | LIBOR | Line of Credit | Revolving Credit Facility
Line of Credit Facility [Line Items]
Basis spread on variable rate			1.25%
Weighted Average | Line of Credit | Revolving Credit Facility
Details for the Credit Facility
Interest rate in the period				3.43%	4.49%