Stockholders' Equity and EPS - Common Shares Excluded from Diluted EPS Calculation as They Were Deemed to be Anti-Dilutive (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from diluted earnings per share calculation	117	638	63	453
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from diluted earnings per share calculation	112	518	61	444
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from diluted earnings per share calculation	5	120	2	9