Consolidated Statement Of Shareholders' Equity (USD $) In Thousands	Common Stock [Member]	Restricted Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) - Unrealized Investment Gain/(Loss) [Member]	Accumulated Other Comprehensive Income (Loss) - Unamortized Actuarial Gain/(Loss) [Member]	Accumulated Other Comprehensive Income (Loss) - Foreign Currency Translation Adjustment [Member]	Total
Balance, value at Dec. 31, 2008	$ 1	$ 7,170	$ 65,739	$ 180,205	$ 87	$ 188	$ (26,560)	$ 226,830
Balance, shares at Dec. 31, 2008	41,265	242
Net income				118,495				118,495
Other Comprehensive Income (loss), net of tax					1	(154)	12,360	12,207
Total Comprehensive Income								130,702
ESPP & Stock Option Activity, shares	36
ESPP & Stock Option Activity			580					580
Restricted stock activity, shares	80	(84)
Restricted stock activity		1,872						1,872
Dividends				(9,946)				(9,946)
Balance, value at Dec. 31, 2009	1	9,042	66,319	288,754	88	34	(14,200)	350,038
Balance, shares at Dec. 31, 2009	41,381	158
Net income				113,593				113,593
Other Comprehensive Income (loss), net of tax					331	(436)	15,598	15,493
Total Comprehensive Income								129,086
ESPP & Stock Option Activity, shares	69
ESPP & Stock Option Activity			1,101					1,101
Restricted stock activity, shares	48	86
Restricted stock activity		1,966						1,966
Dividends				(30,721)				(30,721)
Balance, value at Dec. 31, 2010	1	11,008	67,420	371,626	419	(402)	1,398	451,470
Balance, shares at Dec. 31, 2010	41,498	244
Net income				122,856				122,856
Other Comprehensive Income (loss), net of tax					(255)	315	(73,909)	(73,849)
Total Comprehensive Income								49,007
ESPP & Stock Option Activity, shares	1
ESPP & Stock Option Activity			2					2
Restricted stock activity, shares	72	(1)
Restricted stock activity		2,684						2,684
Dividends				(9,974)				(9,974)
Balance, value at Dec. 31, 2011	$ 1	$ 13,692	$ 67,422	$ 484,508	$ 164	$ (87)	$ (72,511)	$ 493,189
Balance, shares at Dec. 31, 2011	41,571	243