Stock Option Plans - Additional information (Detail) - USD ($) $ / shares in Units, $ in Millions				12 Months Ended
	Mar. 14, 2019	Mar. 15, 2018	Mar. 16, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock Option Plans [Line Items]
Maximum number of shares available				414,700	439,100	476,350
Compensation expense related to stock option grants				$ 14.0	$ 13.7	$ 17.3
Total intrinsic value of options exercised				77.9	$ 54.2	$ 33.7
Total unrecognized compensation cost related to nonvested options				$ 28.2
Weighted average period, years				4 years
Long Term Incentive Plan [Member]
Stock Option Plans [Line Items]
Maximum number of shares available				2,800,000
Shares available for grant				13,200,000
2014 Long Term Incentive Plan [Member]
Stock Option Plans [Line Items]
Number of years options expire from date of grant					7 years	7 years	7 years
Officer and Key Employees [Member] | 2014 Long Term Incentive Plan [Member]
Stock Option Plans [Line Items]
Shares available for grant			1,650,400
Stock options granted, exercise percentage, on the third anniversary date of the grant			34.00%
Stock options granted, exercise percentage, on the fourth anniversary date of the grant			33.00%
Stock options granted, exercise percentage, on the fifth anniversary date of the grant			33.00%
Officer and Key Employees [Member] | 2017 Long Term Incentive Plan [Member]
Stock Option Plans [Line Items]
Shares available for grant	1,283,300	1,261,000
Stock options granted, exercise percentage, on the third anniversary date of the grant	34.00%	34.00%
Stock options granted, exercise percentage, on the fourth anniversary date of the grant	33.00%	33.00%
Stock options granted, exercise percentage, on the fifth anniversary date of the grant	33.00%	33.00%
Maximum [Member] | Long Term Incentive Plan [Member]
Stock Option Plans [Line Items]
Maximum period for the exercise of stock options, years				7 years
Minimum [Member] | Long Term Incentive Plan [Member]
Stock Option Plans [Line Items]
Minimum exercise price of stock options, percent of fair market value of a share of common stock on the date of grant				100.00%
Minimum [Member] | 2014 Long Term Incentive Plan [Member]
Stock Option Plans [Line Items]
Period of service from grant date stock options awarded not subject to forfeiture				2 years	2 years	2 years
Minimum [Member] | Executive Officer [Member] | 2014 Long Term Incentive Plan [Member]
Stock Option Plans [Line Items]
Minimum age of employee with not subject to award forfeiture on condition compliance				55 years	55 years	55 years
Black-Scholes Option Pricing Model [Member]
Stock Option Plans [Line Items]
Weighted average fair value per option for all options				$ 10.71	$ 9.27	$ 11.42