Consolidated Statements of Shareholders' Equity (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Beginning balance at Dec. 31, 2009	$ 711,138	$ 448	$ 574,034	$ (857,130)	$ 1,009,995	$ (16,209)
Beginning balance, shares at Dec. 31, 2009		33,851,124
Exercise of stock options and restricted stock units, shares		527,276
Exercise of stock options and restricted stock units, Value	20,455			39,555	(19,100)
Other Treasury Stock Issuances, Shares		2,549
Other treasury stock issuances, Value	270			183	87
Repurchases of Common Stock, Shares		(1,955,634)
Repurchases of Common Stock, Value	(239,998)			(239,998)
Tax benefit resulting from exercise of certain employee stock options	10,776		10,776
Share-based compensation	12,385		12,385
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	24,410					24,410
Net earnings	232,148				232,148
Ending balance at Dec. 31, 2010	771,584	448	597,195	(1,057,390)	1,223,130	8,201
Ending balance, shares at Dec. 31, 2010		32,425,315
Exercise of stock options and restricted stock units, shares	450,613	450,613
Exercise of stock options and restricted stock units, Value	20,770			36,843	(16,073)
Repurchases of Common Stock, Shares	(1,285,827)	(1,285,827)
Repurchases of Common Stock, Value	(204,578)			(204,578)
Tax benefit resulting from exercise of certain employee stock options	6,737		6,737
Share-based compensation	12,270		12,270
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(95,139)					(95,139)
Net earnings	269,493				269,493
Ending balance at Dec. 31, 2011	781,137	448	616,202	(1,225,125)	1,476,550	(86,938)
Ending balance, shares at Dec. 31, 2011	31,590,101	31,590,101
Exercise of stock options and restricted stock units, shares	457,732	457,732
Exercise of stock options and restricted stock units, Value	21,927			39,873	(17,946)
Repurchases of Common Stock, Shares	(1,637,827)	(1,637,827)
Repurchases of Common Stock, Value	(278,672)			(278,672)
Tax benefit resulting from exercise of certain employee stock options	9,318		9,318
Share-based compensation	13,185		13,185
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(10,523)					(10,523)
Net earnings	290,847				290,847
Ending balance at Dec. 31, 2012	$ 827,219	$ 448	$ 638,705	$ (1,463,924)	$ 1,749,451	$ (97,461)
Ending balance, shares at Dec. 31, 2012	30,410,000	30,410,006