Earnings Per Share (Summary of Share Activity) (Detail)	1 Months Ended	3 Months Ended	12 Months Ended		9 Months Ended
	Jul. 31, 2012	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2012	Sep. 30, 2012 Common Stock [Member]	Sep. 30, 2012 Treasury Stock [Member]
Rollforward of Share Activity, Common and Treasury Shares
Common shares, beginning balance					80,569,000
Treasury shares, beginning balance				9,467,286		4,594,000
Shares issued for stock options					68,000
Shares issued for restricted stock					143,000
Other shares issued					61,000
Common stock repurchases	2,000,000	2,900,000	4,600,000		4,873,000	4,873,000
Common shares, ending balance					75,968,000
Treasury shares, ending balance			4,593,663	9,467,286		9,467,000