CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
NET INCOME	$ 18,652	$ 44,854	$ 46,177
Pension and other postretirement benefit plans:
Net actuarial loss, net of tax of: (2016 – $805; 2015 – $4,798; 2014 – $8,639)	(1,267)	(7,535)	(13,567)
Pension settlement expense, net of tax of: (2016 – $1,256; 2015 – $1,246; 2014 – $2,565)	1,973	1,956	4,030
Amortization of unrecognized net periodic benefit costs, net of tax of: (2016 – $1,849; 2015 – $1,571; 2014 – $979)
Net actuarial loss	3,021	2,585	1,652
Prior service credit	(116)	(116)	(116)
Interest rate swap and foreign currency translation:
Change in unrealized income (loss) on interest rate swap, net of tax of: (2016 – $139; 2015 – $126; 2014 – $226)	216	(195)	(350)
Change in foreign currency translation, net of tax of: (2016 – $149 ; 2015 – $451; 2014 – $137)	252	(712)	(216)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	4,079	(4,017)	(8,567)
TOTAL COMPREHENSIVE INCOME	$ 22,731	$ 40,837	$ 37,610