XML 67 R56.htm IDEA: XBRL DOCUMENT v3.10.0.1
Stock-Based Compensation - Restricted Stock Units Unvested Roll Forward (Detail) - Restricted Stock Units (RSUs) [Member]
shares in Thousands
6 Months Ended
Jun. 30, 2018
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]  
Unvested Beginning balance, Shares | shares 374
Shares,Granted | shares 88
Shares,Vested | shares (116)
Shares,Forfeited | shares (12)
Unvested Ending balance, Shares | shares 334
Weighted-average grant date fair value per share of shares unvested at beginning of period | $ / shares $ 124.81
Weighted-average grant date fair value per share of shares granted | $ / shares 208.26
Weighted-average grant date fair value per share of shares vested | $ / shares 117.35
Weighted-average grant date fair value of shares forfeited | $ / shares 118.07
Weighted-average grant date fair value per share of shares unvested at end of period | $ / shares $ 149.63