Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Unrealized gain (loss) on available-for-sale marketable securities, net of taxes	$ 2,761	$ (679)	$ 1,156
Quoted Prices in Active Markets (Level 1) | RSP
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gain related to equity securities	7,400
Unrealized loss related to equity securities		(1,300)
Municipal bonds — available-for-sale
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Proceeds from available for sale municipal bonds	21,300	9,000	28,500
Realized loss (less than $0.2 million for 2018 and less than $0.1 for 2017)	$ 100	$ 200	$ 100