CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY AND COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	Total		Common Stock and Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Earnings (Loss)	Annual Comprehensive Earnings
Balance at beginning of period at Dec. 31, 2008	$ 844,725		$ 282,849	$ 577,090	$ (15,214)
Balance (in shares) at beginning of period at Dec. 31, 2008			141,387
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive earnings						252,557
Net earnings for the year	230,213			230,213		230,213
Income tax benefit of common stock options exercised	9,245		9,245
Repurchase of common stock (in shares)			(3,232)
Repurchase of common stock	(73,169)		(73,169)
Common stock issued pursuant to stock-based compensation plans, net (in shares)			2,717
Common stock issued pursuant to stock-based compensation plans, net	17,581		17,581
Stock-based compensation expense	23,888		23,888
Conversion of convertible debt (in shares)			11,954
Conversion of convertible debt	128,427		128,427
Capital contribution	495		495
Change in minimum liability for pension plans, net of tax effects	781				781	781
Translation adjustment	21,563				21,563	21,563
Balance at end of period at Dec. 31, 2009	1,203,749		389,316	807,303	7,130
Balance (in shares) at end of period at Dec. 31, 2009			152,826
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive earnings						242,648
Net earnings for the year	248,126	[1]		248,126		248,126
Income tax benefit of common stock options exercised	8,263		8,263
Repurchase of common stock (in shares)			(1,306)
Repurchase of common stock	(35,725)		(35,725)
Common stock issued pursuant to stock-based compensation plans, net (in shares)			2,397
Common stock issued pursuant to stock-based compensation plans, net	17,388		17,388
Stock-based compensation expense	25,352		25,352
Conversion of convertible debt (in shares)			5,295
Conversion of convertible debt	58,752		58,752
Capital contribution	2,121		2,121
Change in minimum liability for pension plans, net of tax effects	664				664	664
Translation adjustment	(6,142)				(6,142)	(6,142)
Balance at end of period at Dec. 31, 2010	1,522,548		465,467	1,055,429	1,652
Balance (in shares) at end of period at Dec. 31, 2010			159,212
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive earnings						207,828
Net earnings for the year	221,474			221,474		221,474
Income tax benefit of common stock options exercised	5,545		5,545
Repurchase of common stock (in shares)			(6,135)
Repurchase of common stock	(160,669)		(160,669)
Common stock issued pursuant to stock-based compensation plans, net (in shares)			1,892
Common stock issued pursuant to stock-based compensation plans, net	16,751		16,751
Stock-based compensation expense	25,063		25,063
Dividends paid	(38,037)			(38,037)
Change in minimum liability for pension plans, net of tax effects	(1,113)				(1,113)	(1,113)
Translation adjustment	(12,533)				(12,533)	(12,533)
Balance at end of period at Dec. 31, 2011	$ 1,579,029		$ 352,157	$ 1,238,866	$ (11,994)
Balance (in shares) at end of period at Dec. 31, 2011			154,969

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