Condensed Consolidated Statements of Stockholders' Equity (USD $) In Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Comprehensive Income
Balance at Dec. 31, 2009	$ 763,784	$ 493	$ 146,036	$ 598,493	$ 18,762
Balance (in shares) at Dec. 31, 2009		49,377
Comprehensive income:
Net income	15,903			15,903			15,903
Other comprehensive income:
Translation adjustment, net of tax expense of $1, $9, and $3 for the six months ended June 30, 2011, December 31, 2010, and June 30, 2010, respectively	(18,013)				(18,013)		(18,013)
Comprehensive income	(2,110)						(2,110)
Stock options exercised	955	1	954
Stock options exercised (in shares)		39
Stock compensation	561		561
Tax effect of options exercised	(83)		(83)
Cash dividends declared on common stock, $0.25, $0.20, and $0.20 per share for the six months ended June 30, 2011, December 31, 2010, and June 30, 2010, respectively	(9,917)			(9,917)
Common stock issued for stock bonus at $30.91, $22.04, and $26.89 per share for the six months ended June 30, 2011, December 31, 2010, and June 30, 2010, respectively	277		277
Common stock issued (in shares)		10
Balance at Jun. 30, 2010	753,467	494	147,745	604,479	749
Balance (in shares) at Jun. 30, 2010		49,426
Comprehensive income:
Net income	12,683			12,683			12,683
Other comprehensive income:
Translation adjustment, net of tax expense of $1, $9, and $3 for the six months ended June 30, 2011, December 31, 2010, and June 30, 2010, respectively	13,878				13,878		13,878
Comprehensive income	26,561						26,561
Stock options exercised	16,993	6	16,987
Stock options exercised (in shares)		668
Stock compensation	3,016		3,016
Tax effect of options exercised	(2,347)		(2,347)
Cash dividends declared on common stock, $0.25, $0.20, and $0.20 per share for the six months ended June 30, 2011, December 31, 2010, and June 30, 2010, respectively	(9,921)			(9,921)
Common stock issued for stock bonus at $30.91, $22.04, and $26.89 per share for the six months ended June 30, 2011, December 31, 2010, and June 30, 2010, respectively	24		24
Common stock issued (in shares)		2
Balance at Dec. 31, 2010	787,793	500	165,425	607,241	14,627
Balance (in shares) at Dec. 31, 2010		50,096
Comprehensive income:
Net income	26,571			26,571			26,571
Other comprehensive income:
Translation adjustment, net of tax expense of $1, $9, and $3 for the six months ended June 30, 2011, December 31, 2010, and June 30, 2010, respectively	10,252				10,252		10,252
Comprehensive income	36,823						36,823
Stock options exercised	154		154
Stock options exercised (in shares)		6
Stock compensation	2,118		2,118
Tax effect of options exercised	(39)		(39)
Repurchase of common stock	(50,075)					(50,075)
Repurchase of common stock (in shares)		(1,828)
Retirement of common stock		(18)		(50,057)		50,075
Cash dividends declared on common stock, $0.25, $0.20, and $0.20 per share for the six months ended June 30, 2011, December 31, 2010, and June 30, 2010, respectively	(12,526)			(12,526)
Common stock issued for stock bonus at $30.91, $22.04, and $26.89 per share for the six months ended June 30, 2011, December 31, 2010, and June 30, 2010, respectively	204		204
Common stock issued (in shares)		7
Balance at Jun. 30, 2011	$ 764,452	$ 482	$ 167,862	$ 571,229	$ 24,879
Balance (in shares) at Jun. 30, 2011		48,281