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		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Accounting Policies [Abstract]
Basic weighted average common shares outstanding (in shares)	77,466	80,106	77,731	80,317
Dilutive effect of stock options, unvested shares, and DCUs (in shares)	831	1,043	845	1,045
Diluted weighted average common shares outstanding (in shares)	78,297	81,149	78,576	81,362