Capital Stock - Additional Information (Detail) - USD ($)	3 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2020	Oct. 31, 2019
Class Of Stock Disclosures [Abstract]
Authorized capital stock	485,000,000.0								485,000,000.0
Common stock, shares authorized	475,000,000								475,000,000
Preferred stock, shares authorized	10,000,000								10,000,000
Common dividends declared per share	$ 0.02	$ 0.02	$ 0.02	$ 0.02	$ 0.02	$ 0.02	$ 0.02	$ 0.02
Maximum
Class Of Stock Disclosures [Abstract]
New stock purchase program, approved amount										$ 100,000,000