Changes in Shareholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Balance			$ 547,779
Net income/(loss)	11,177	(7,379)	21,870	4,132
Dividends declared			(9,868)
Compensation and benefits paid or payable in Class A Common Stock			798
Options exercised			531
Shares issued to Directors			150
Cumulative translation adjustment			(1,838)
Change in pension liability adjustment			178
Change in derivative valuation adjustment			(222)
Balance	559,378		559,378
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			416,728
Net income/(loss)
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock			798
Options exercised			531
Shares issued to Directors			60
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	418,117		418,117
Retained Earnings [Member]
Balance			434,598
Net income/(loss)			21,840
Dividends declared			(9,868)
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	446,570		446,570
Accumulated Items of Other Comprehensive Income [Member]
Balance			(49,498)
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			(1,838)
Change in pension liability adjustment			178
Change in derivative valuation adjustment			(222)
Balance	(51,380)		(51,380)
Treasury Stock [Member]
Balance			(257,571)
Net income/(loss)
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Shares issued to Directors			90
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	(257,571)		(257,571)
Noncontrolling Interest [Member]
Balance			3,482
Net income/(loss)			30
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	$ 3,512		$ 3,512