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, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from diluted earnings per share calculation	91	117	120	63
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from diluted earnings per share calculation	86	112	49	61
Restricted stock units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares excluded from diluted earnings per share calculation	5	5	71	2