XML 53 R55.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Stock-Based Compensation - Fair Value of Market Performance Units Estimated, Monte Carlo Simulation Model (Detail) - Market Performance Units [Member]
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Risk-free interest rate, Minimum 1.59% 2.46% 1.76%
Risk-free interest rate, Maximum 1.62% 2.63% 1.98%
Estimated volatility factor, Minimum 40.00% 29.00% 27.00%
Estimated volatility factor, Maximum 55.00% 32.00% 31.00%
Expected dividends 0.00% 0.00% 0.00%