Quarterly Results - Additional Information (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
ASU 2016-09
Quarterly Financial Information [Line Items]
Unfavorable after-tax reduction	$ 3,000,000.0	$ 3,100,000	$ 505,000	$ 770,000
Tax reduction per diluted share	$ 0.04	$ 0.04	$ 0.01	$ 0.01
Favorable after tax impact					$ 1,700,000	$ 509,000	$ 10,900,000
Favorable after tax impact per share diluted					$ 0.02	$ 0.01	$ 0.12
Unrealized Loss on Marketable Securities Held for Sale
Quarterly Financial Information [Line Items]
Unfavorable after-tax reduction		$ 2,100,000		$ 7,400,000
Tax reduction per diluted share		$ 0.02		$ 0.08
Unrealized Gain on Marketable Securities Held for Sale
Quarterly Financial Information [Line Items]
Unfavorable after-tax reduction	$ 3,900,000		$ 2,200,000
Tax reduction per diluted share	$ 0.05		$ 0.03
DOJ Reserve
Quarterly Financial Information [Line Items]
Unfavorable after-tax reduction					$ 6,200,000	$ 8,400,000
Tax reduction per diluted share					$ 0.07	$ 0.09
Unfavorable pre-tax reduction						$ 11,000,000.0
Provision For Asset Impairment
Quarterly Financial Information [Line Items]
Unfavorable after-tax reduction					$ 74,600,000
Tax reduction per diluted share					$ 0.84
Unfavorable pre-tax reduction					$ 97,600,000