Earnings Per Common Share (Schedule of Basic Weighted Average Shares Reconciles to Diluted Weighted Average Shares Outstanding) (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accounting Policies [Abstract]
Basic weighted average common shares outstanding (in shares)	76,831	79,558	77,431	80,064
Dilutive effect of stock options, unvested shares, and DCUs (in shares)	815	1,003	835	1,029
Diluted weighted average common shares outstanding (in shares)	77,646	80,561	78,266	81,093