Reconciliation of the Numerator and Denominator Utilized in the Computation of Basic and Diluted Earnings Per Share (Detail) (USD $) In Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Numerator for earnings per share:
Earnings from continuing operations	$ 64,390	$ 62,955	$ 145,818	$ 178,304
Income (loss) from discontinued operations	329		(475)
Net earnings available to common shareholders - basic	64,719	62,955	145,343	178,304
Interest associated with convertible notes, net of tax				935
Net earnings available to common shareholders - diluted	$ 64,719	$ 62,955	$ 145,343	$ 179,239
Denominator for earnings per share:
Weighted average number of common shares outstanding	158,665	158,215	159,225	155,223
Assumed exercises of stock options and vesting of restricted stock awards, net of shares assumed reacquired under the treasury stock method	2,133	2,710	2,586	3,151
Assumed conversion of convertible notes				3,066
Weighted average diluted shares outstanding	160,798	160,925	161,811	161,440
Anti-dilutive shares of stock-based compensation awards excluded	731	517	307	421

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