Shareholders' Equity (Schedule of Activity in Shareholders' Equity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Balance	$ 493,511
Balance, shares	31,400,000	31,300,000
Net income	17,658	30,977	34,938
Balance	547,779	493,511
Balance, shares	31,800,000	31,400,000	31,300,000
Common Class B [Member]
Balance, shares	3,236,098	3,236,098
Common Stock [Member] | Common Class A [Member]
Balance	37	37	36
Balance, shares	36,642,000	36,541,000	36,442,000
Compensation and benefits paid or payable in shares			1
Compensation and benefits paid or payable in shares, shares	75,000	34,000	57,000
Sale of Noncontrolling interest in ASC, net of tax
Options exercised
Options exercised, shares	279,000	67,000	42,000
Shares issued to Directors
Shares issued to Directors, shares
Net income
Dividends declared
Cumulative translation adjustments
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	37	37	37
Balance, shares	36,996,000	36,642,000	36,541,000
Common Stock [Member] | Common Class B [Member]
Balance	3	3	3
Balance, shares	3,236,000	3,236,000	3,236,000
Compensation and benefits paid or payable in shares
Compensation and benefits paid or payable in shares, shares
Sale of Noncontrolling interest in ASC, net of tax
Options exercised
Options exercised, shares
Shares issued to Directors
Shares issued to Directors, shares
Net income
Dividends declared
Cumulative translation adjustments
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	3	3	3
Balance, shares	3,236,000	3,236,000	3,236,000
Additional Paid-in Capital [Member]
Balance	395,381	391,495	387,876
Compensation and benefits paid or payable in shares	(902)	2,573	2,712
Sale of Noncontrolling interest in ASC, net of tax	15,535
Options exercised	6,670	1,352	883
Shares issued to Directors	44	(39)	24
Net income
Dividends declared
Cumulative translation adjustments
Settlement of certain pension plan liabilities
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	416,728	395,381	391,495
Retained Earnings [Member]
Balance	435,775	422,044	403,048
Compensation and benefits paid or payable in shares
Sale of Noncontrolling interest in ASC, net of tax
Options exercised
Shares issued to Directors
Net income	17,517	30,977	34,938
Dividends declared	(18,694)	(17,246)	(15,942)
Cumulative translation adjustments
Settlement of certain pension plan liabilities
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	434,598	435,775	422,044
Accumulated Other Comprehensive Income (Loss) [Member]
Balance	(80,021)	(139,809)	(106,672)
Compensation and benefits paid or payable in shares
Sale of Noncontrolling interest in ASC, net of tax
Options exercised
Shares issued to Directors
Net income
Dividends declared
Cumulative translation adjustments	7,521	11,452	(13,070)
Settlement of certain pension plan liabilities		79,204
Pension and postretirement liability adjustments	21,101	(30,584)	(17,749)
Derivative valuation adjustment	1,901	(284)	(2,318)
Balance	(49,498)	(80,021)	(139,809)
Treasury Stock [Member]
Balance	(257,664)	(257,920)	(258,031)
Balance, shares	(8,468,000)	(8,480,000)	(8,485,000)
Compensation and benefits paid or payable in shares
Compensation and benefits paid or payable in shares, shares
Sale of Noncontrolling interest in ASC, net of tax
Options exercised
Options exercised, shares
Shares issued to Directors	93	256	111
Shares issued to Directors, shares	4,000	12,000	5,000
Net income
Dividends declared
Cumulative translation adjustments
Settlement of certain pension plan liabilities
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	(257,571)	(257,664)	(257,920)
Balance, shares	(8,464,000)	(8,468,000)	(8,480,000)
Noncontrolling Interest [Member]
Balance
Compensation and benefits paid or payable in shares
Sale of Noncontrolling interest in ASC, net of tax	3,341
Options exercised
Shares issued to Directors
Net income	141
Dividends declared
Cumulative translation adjustments
Settlement of certain pension plan liabilities
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	$ 3,482