Consolidated Statement of Changes in Retained Earnings and Accumulated Other Comprehensive Loss (Unaudited) Statement (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 572,347
Net income	19,205	19,177	55,617	62,963
Pension and post-retirement plan adjustments net of tax of three and nine months 2014: $805 and $3,239 and three and nine months 2013: $1,275 and $3,831	1,418	2,107	5,718	6,321
Ending balance	589,658		589,658
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	806,219	769,755	792,206	747,953
Net income	19,205	19,177	55,617	62,963
Loss (income) attributable to noncontrolling interests	100	324	202	(127)
Common dividends	(11,532)	(11,151)	(34,013)	(32,664)
Preferred dividends	(10)	(10)	(30)	(30)
Ending balance	813,982	778,095	813,982	778,095
Accumulated Other Comprehensive (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(74,731)	(135,163)	(78,269)	(127,072)
Foreign currency translation adjustments	(20,563)	6,158	(21,467)	(7,068)
Pension and post-retirement plan adjustments net of tax of three and nine months 2014: $805 and $3,239 and three and nine months 2013: $1,275 and $3,831	1,418	2,107	5,718	6,321
Loss (income) attributable to noncontrolling interests	280	(4)	422	917
Ending balance	$ (93,596)	$ (126,902)	$ (93,596)	$ (126,902)