Changes in Shareholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Balance			$ 493,511
Net income/(loss)	(7,379)	(33,745)	4,132	13,296
Dividends declared			(9,171)
Compensation and benefits paid or payable in Class A Common Stock			(1,311)
Options exercised			3,492
Shares issued to Directors			137
Cumulative translation adjustment			(14,494)
Change in pension liability adjustment			2,229
Change in derivative valuation adjustment			1,752
Balance	480,277		480,277
Common Stock [Member] | Common Class A [Member]
Balance			37
Net income/(loss)
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/(loss)
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/(loss)
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock			(1,311)
Options exercised			3,492
Shares issued to Directors			44
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	397,606		397,606
Retained Earnings [Member]
Balance			435,775
Net income/(loss)			4,132
Dividends declared			(9,171)
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	430,736		430,736
Accumulated Items of Other Comprehensive Income [Member]
Balance			(80,021)
Net income/(loss)
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Shares issued to Directors
Cumulative translation adjustment			(14,494)
Change in pension liability adjustment			2,229
Change in derivative valuation adjustment			1,752
Balance	(90,534)		(90,534)
Treasury Stock [Member]
Balance			(257,664)
Net income/(loss)
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)