Changes in Shareholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Balance	$ 547,779
Net income	10,693	11,511
Dividends declared	(4,773)
Compensation and benefits paid or payable in Class A Common Stock	541
Options exercised	165
Cumulative translation adjustment	(5,599)
Change in pension liability adjustment	502
Change in derivative valuation adjustment	72
Balance	549,380
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
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	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
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	3
Additional Paid-in Capital [Member]
Balance	416,728
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock	541
Options exercised	165
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	417,434
Retained Earnings [Member]
Balance	434,598
Net income	10,621
Dividends declared	(4,773)
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	440,446
Accumulated Items of Other Comprehensive Income [Member]
Balance	(49,498)
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Cumulative translation adjustment	(5,599)
Change in pension liability adjustment	502
Change in derivative valuation adjustment	72
Balance	(54,523)
Treasury Stock [Member]
Balance	(257,571)
Net income
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	(257,571)
Noncontrolling Interest [Member]
Balance	3,482
Net income	72
Dividends declared
Compensation and benefits paid or payable in Class A Common Stock
Options exercised
Cumulative translation adjustment
Change in pension liability adjustment
Change in derivative valuation adjustment
Balance	$ 3,554