Quarterly Financial Data (Unaudited) (Details) (USD $)	0 Months Ended		3 Months Ended												12 Months Ended
	May 20, 2011	Oct. 27, 2010	Dec. 31, 2011	Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2010		Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010		Dec. 31, 2009
Quarterly Financial Information Disclosure [Abstract]
Revenue			$ 405,212,000	$ 371,327,000	[1]	$ 391,554,000	[1]	$ 375,969,000	[1]	$ 437,509,000	[1]	$ 332,497,000	$ 331,133,000	$ 287,298,000	$ 1,544,062,000	$ 1,388,437,000	[2]	$ 1,147,087,000
Gross profit			224,785,000	201,897,000	[1]	205,410,000	[1]	196,512,000	[1]	232,856,000	[1]	182,108,000	183,323,000	165,354,000	828,604,000	763,641,000	[2]	658,529,000
Earnings from continuing operations			76,835,000	64,390,000	[1]	29,822,000	[1],[3]	51,605,000	[1]	70,070,000	[1]	62,955,000	59,454,000	55,895,000	222,652,000	248,374,000	[2]	230,213,000
(Loss) from discontinued operations			(705,000)	329,000	[1]	(513,000)	[1]	(289,000)	[1]	(248,000)	[1]	0	0	0	(1,178,000)	(248,000)	[2]	0
Net earnings			76,130,000	64,719,000	[1]	29,309,000	[1]	51,316,000	[1]	69,822,000	[1]	62,955,000	59,454,000	55,895,000	221,474,000	248,126,000	[2]	230,213,000
Basic earnings per share:
Continuing operations			$ 0.49	$ 0.41	[1]	$ 0.19	[1]	$ 0.32	[1]	$ 0.44	[1]	$ 0.40	$ 0.38	$ 0.37	$ 1.41	$ 1.59	[2]	$ 1.54
Discontinued operations			$ 0.00	$ 0.00	[1]	$ 0.00	[1]	$ 0.00	[1]	$ 0.00	[1]	$ 0.00	$ 0.00	$ 0.00	$ (0.01)	$ 0.00	[2]	$ 0.00
Basic earnings per share			$ 0.49	$ 0.41	[1]	$ 0.18	[1]	$ 0.32	[1]	$ 0.44	[1]	$ 0.40	$ 0.38	$ 0.37	$ 1.40	$ 1.59	[2]	$ 1.54
Diluted earnings per share:
Continuing operations			$ 0.49	$ 0.40	[1]	$ 0.18	[1]	$ 0.32	[1]	$ 0.44	[1]	$ 0.39	$ 0.37	$ 0.35	$ 1.38	$ 1.54	[2]	$ 1.45
Discontinued operations			$ 0.00	$ 0.00	[1]	$ 0.00	[1]	$ 0.00	[1]	$ 0.00	[1]	$ 0.00	$ 0.00	$ 0.00	$ (0.01)	$ 0.00	[2]	$ 0.00
Diluted earnings per share			$ 0.48	$ 0.40	[1]	$ 0.18	[1]	$ 0.32	[1]	$ 0.43	[1]	$ 0.39	$ 0.37	$ 0.35	$ 1.38	$ 1.54	[2]	$ 1.45
Litigation settlement payment	$ 39,000,000	$ 3,000,000				$ 39,000,000

[1] Amounts for the fourth quarter of 2010 and the first three quarters of 2011 have been adjusted for the reclassification of certain discontinued operations to continuing operations.

[2] Amounts have been adjusted for the reclassification of certain discontinued operations to continuing operations.

[3] Earnings from continuing operations for the second quarter of 2011 include the payment of a $39 million litigation settlement. See Note 13 to the Consolidated Financial Statements for additional information.