Changes in Shareholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Balance			$ 513,568
Compensation and benefits paid or payable in shares			829
Options exercised			2,327
Shares issued to Directors			166
Net income/(loss)	$ (2,120)	$ 11,177	10,119	$ 21,870
Dividends declared			(10,549)
Cumulative translation adjustment			(26,022)
Pension and postretirement liability adjustments			1,610
Derivative valuation adjustment			(163)
Balance	491,885		491,885
Common Stock [Member]
Balance			$ 40
Compensation and benefits paid or payable in shares
Options exercised
Shares issued to Directors
Net income/(loss)
Dividends declared
Cumulative translation adjustment
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	40		$ 40
Additional Paid-in Capital [Member]
Balance			418,972
Compensation and benefits paid or payable in shares			829
Options exercised			2,327
Shares issued to Directors			$ 76
Net income/(loss)
Dividends declared
Cumulative translation adjustment
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	422,204		$ 422,204
Retained Earnings [Member]
Balance			$ 456,105
Compensation and benefits paid or payable in shares
Options exercised
Shares issued to Directors
Net income/(loss)			$ 10,041
Dividends declared			$ (10,549)
Cumulative translation adjustment
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	455,597		$ 455,597
Accumulated Items of Other Comprehensive Income [Member]
Balance			$ (107,767)
Compensation and benefits paid or payable in shares
Options exercised
Shares issued to Directors
Net income/(loss)
Dividends declared
Cumulative translation adjustment			$ (26,023)
Pension and postretirement liability adjustments			1,610
Derivative valuation adjustment			(163)
Balance	(132,343)		(132,343)
Treasury Stock [Member]
Balance			$ (257,481)
Compensation and benefits paid or payable in shares
Options exercised
Shares issued to Directors			$ 90
Net income/(loss)
Dividends declared
Cumulative translation adjustment
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	(257,391)		$ (257,391)
Noncontrolling Interest [Member]
Balance			$ 3,699
Compensation and benefits paid or payable in shares
Options exercised
Shares issued to Directors
Net income/(loss)			$ 78
Dividends declared
Cumulative translation adjustment			$ 1
Pension and postretirement liability adjustments
Derivative valuation adjustment
Balance	$ 3,778		$ 3,778