Quarterly Financial Data (Unaudited) (Details) (USD $)	0 Months Ended		3 Months Ended												12 Months Ended
	May 20, 2011	Oct. 27, 2010	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
Quarterly Financial Information Disclosure [Abstract]
Revenue			$ 400,319,000	$ 358,141,000	$ 389,329,000	$ 348,583,000	$ 386,385,000		$ 332,230,000		$ 338,291,000		$ 348,452,000		$ 1,496,372,000	$ 1,405,358,000	$ 1,544,062,000
Gross profit			190,092,000	172,890,000	190,041,000	183,987,000	205,375,000	[1]	173,665,000	[1]	173,417,000	[1]	182,727,000	[1]	737,010,000	735,184,000	829,319,000
Earnings from continuing operations							78,177,000		55,949,000		42,405,000		48,825,000		177,015,000	225,356,000	222,652,000
(Loss) income from discontinued operations							(916,000)		(44,000)		(1,312,000)		(686,000)		0	(2,958,000)	(1,178,000)
Net earnings			28,735,000	46,486,000	50,158,000	51,636,000	77,261,000		55,905,000		41,093,000		48,139,000		177,015,000	222,398,000	221,474,000
Basic earnings per share:
Continuing operations							$ 0.53		$ 0.37		$ 0.28		$ 0.32		$ 1.24	$ 1.49	$ 1.41
Discontinued operations							$ (0.01)		$ 0.00		$ (0.01)		$ 0.00		$ 0.00	$ (0.02)	$ (0.01)
Basic earnings per share			$ 0.20	$ 0.33	$ 0.35	$ 0.36	$ 0.52		$ 0.37		$ 0.27		$ 0.31		$ 1.24	$ 1.47	$ 1.40
Diluted earnings per share:
Continuing operations							$ 0.52		$ 0.37		$ 0.27		$ 0.31		$ 1.22	$ 1.47	$ 1.38
Discontinued operations							$ (0.01)		$ 0.00		$ (0.01)		$ 0.00		$ 0.00	$ (0.02)	$ (0.01)
Diluted earnings per share			$ 0.20	$ 0.32	$ 0.35	$ 0.35	$ 0.52		$ 0.37		$ 0.27		$ 0.31		$ 1.22	$ 1.45	$ 1.38
Litigation settlement payment	$ 39,000,000	$ 3,000,000

[1] Certain expenses have been reclassified to conform to the presentation for the quarterly data of 2013.