Subsequent Events - Additional Information (Detail) - USD ($)	Feb. 06, 2020	Dec. 31, 2019	Dec. 19, 2019	Dec. 31, 2018	Mar. 22, 2017
Subsequent Event [Line Items]
Line of credit facility maximum borrowing capacity		$ 550,000,000	$ 400,000,000	$ 475,000,000	$ 50,000,000
Subsequent Event [Member] | 364-day Credit Agreement [Member]
Subsequent Event [Line Items]
Credit facility maturity period	364 days
Line of credit facility maximum borrowing capacity	$ 300,000,000