Annual report pursuant to Section 13 and 15(d)

Stock Compensation Plans (Black-Scholes Option Pricing Weighted-Average Assumptions) (Detail)

v3.6.0.2
Stock Compensation Plans (Black-Scholes Option Pricing Weighted-Average Assumptions) (Detail) - Employee and Director Option
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Dividend yield 0.00% 0.00% 0.00%
Expected volatility 50.38% 61.10% 64.94%
Risk-free interest rate 1.67% 1.63% 2.02%
Expected life (in years) 6 years 1 month 10 days 6 years 1 month 24 days 6 years 4 months 24 days