Basis and Summary of Significant Accounting Policies Calculation of Dilutive Stock Awards (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Weighted average shares outstanding	72,572	72,246	72,544	72,356
Dilutive effect of share-based awards (in shares)	393	352	366	377
Weighted average shares outstanding assuming dilution	72,965	72,598	72,910	72,733