Schedule of Basic Weighted Average Shares Reconciles to Diluted Weighted Average Shares Outstanding (Detail) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounting Policies [Abstract]
Basic weighted average common shares outstanding	80,782	81,259	81,829	82,197	82,296	82,482	83,180	82,804	81,517	82,689	82,145
Dilutive effect of stock options, unvested shares, performance share units and DCUs									972	952	1,398
Diluted weighted average common shares outstanding	81,854	82,218	82,734	83,152	82,296	83,370	84,090	83,902	82,489	83,641	83,543