Changes in Stockholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Balance			$ 415,850
Net income	9,463	16,674	22,759	42,169
Dividends declared			(12,849)
Compensation and benefits paid or payable in Class A Common Stock			1,446
Options exercised			1,116
Currency translation adjustment			3,899
Pension settlement			79,204
Pension plan remeasurement			(17,347)
Change in pension liability adjustment			2,645
Change in derivative valuation adjustment			(548)
Balance	496,175		496,175
Class A Common Stock [Member]
Balance			37
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Currency translation adjustment
Pension settlement
Pension plan remeasurement
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	37		37
Class B Common Stock [Member]
Balance			3
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Currency translation adjustment
Pension settlement
Pension plan remeasurement
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	3		3
Additional Paid-in Capital [Member]
Balance			391,495
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock			1,190
Options exercised			1,116
Currency translation adjustment
Pension settlement
Pension plan remeasurement
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	393,801		393,801
Retained Earnings [Member]
Balance			422,044
Net income			22,759
Dividends declared			(12,849)
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Currency translation adjustment
Pension settlement
Pension plan remeasurement
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	431,954		431,954
Accumulated Items of Other Comprehensive Income [Member]
Balance			(139,809)
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Currency translation adjustment			3,899
Pension settlement			79,204
Pension plan remeasurement			(17,347)
Change in pension liability adjustment			2,645
Change in derivative valuation adjustment			(548)
Balance	(71,956)		(71,956)
Treasury Stock [Member]
Balance			(257,920)
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock			256
Options exercised
Currency translation adjustment
Pension settlement
Pension plan remeasurement
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	$ (257,664)		$ (257,664)