CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
NET INCOME	$ 10,231	$ 19,967	$ 4,128	$ 20,712
Pension and other postretirement benefit plans:
Net actuarial gain (loss), net of tax of: (2016 – Three-month period $1,229, Six-month period $3,459; 2015 – Three-month period $1,515, Six-month period $349)	(1,931)	2,379	(5,435)	548
Pension settlement expense, net of tax of: (2016 – Three-month period $219, Six-month period $569; 2015 – Three-month period $233, Six-month period $668)	345	364	895	1,048
Amortization of unrecognized net periodic benefit costs, net of tax of: (2016 – Three-month period $477, Six-month period $914 ; 2015 – Three-month period $396, Six-month period $796)
Net actuarial loss	780	653	1,494	1,309
Prior service credit	(29)	(29)	(58)	(58)
Interest rate swap and foreign currency translation:
Change in unrealized income (loss) on interest rate swap, net of tax of: (2016 – Three-month period $93, Six-month period $446; 2015 – Three-month period $158, Six-month period $77)	(146)	244	(692)	(120)
Change in foreign currency translation, net of tax of: (2016 – Three-month period $86, Six-month period $285; 2015 – Three-month period $61, Six-month period $126)	(135)	97	449	(198)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(1,116)	3,708	(3,347)	2,529
TOTAL COMPREHENSIVE INCOME	$ 9,115	$ 23,675	$ 781	$ 23,241