Basis and Summary of Significant Accounting Policies - Calculation of Dilutive Stock Awards (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accounting Policies [Abstract]
Weighted average shares outstanding	72,608	72,586	72,667	72,558
Dilutive effect of share-based awards (in shares)	591	490	564	408
Weighted average shares outstanding assuming dilution	73,199	73,076	73,231	72,966
Anti-dilutive securities excluded from the computation of earnings per share assuming dilution (in shares)	1,193	281	1,102	431