Changes in Shareholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Balance			$ 493,511
Net income	4,698	9,463	8,830	22,759
Dividends declared			(13,929)
Compensation and benefits paid or payable in Class A Common Stock			(1,024)
Options exercised			5,572
Shares issued to Directors			137
Cumulative translation adjustment			3,998
Change in pension liability adjustment			15,613
Change in derivative valuation adjustment			1,509
Balance	514,217		514,217
Common Stock [Member] | Common Class A [Member]
Balance			37
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Shares issued to Directors
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	37		37
Common Stock [Member] | Common Class B [Member]
Balance			3
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Shares issued to Directors
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	3		3
Additional Paid-in Capital [Member]
Balance			395,381
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock			(1,024)
Options exercised			5,572
Shares issued to Directors			44
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	399,973		399,973
Retained Earnings [Member]
Balance			435,775
Net income			8,830
Dividends declared			(13,929)
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Shares issued to Directors
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	430,676		430,676
Accumulated Items of Other Comprehensive Income [Member]
Balance			(80,021)
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Shares issued to Directors
Cumulative translation adjustment			3,998
Change in pension liability adjustment			15,613
Change in derivative valuation adjustment			1,509
Balance	(58,901)		(58,901)
Treasury Stock [Member]
Balance			(257,664)
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Shares issued to Directors			93
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	$ (257,571)		$ (257,571)