Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2020

Financial Instruments, Owned, at Fair Value [Abstract]

Estimated Fair Values of Financial Instruments

The following table presents the fair values of financial instruments:

	December 31,
	2020		2019
	(Amounts in thousands)
Assets
Investments	$	4,729,270	$	4,312,161
Note receivable	5,725		5,665
Liabilities
Options sold	—		77
Unsecured notes	415,253		394,279