Pension Plans and Postretirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions by Employer	$ 500
CANADA
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	107	$ 99
Defined Benefit Plan, Interest Cost	140	130
Defined Benefit Plan, Expected Return on Plan Assets	(201)	(185)
Defined Benefit Plan, Amortization of Gains (Losses)	43	50
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	27	25
Defined Benefit Plan, Other Costs	6	6
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Plan Assets	(34)	(210)
Defined Benefit Plan, Net Periodic Benefit Cost	88	(85)
UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	34	46
Defined Benefit Plan, Interest Cost	56	73
Defined Benefit Plan, Expected Return on Plan Assets	(35)	(36)
Defined Benefit Plan, Amortization of Gains (Losses)	(50)	(11)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0
Defined Benefit Plan, Net Periodic Benefit Cost	5	72
Defined Contribution Plan, Employer Discretionary Contribution Amount	2,900
Pension Benefits [Member] | CANADA
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	94	87
Defined Benefit Plan, Interest Cost	127	118
Defined Benefit Plan, Expected Return on Plan Assets	(201)	(185)
Defined Benefit Plan, Amortization of Gains (Losses)	43	50
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	27	25
Defined Benefit Plan, Other Costs	0	0
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Plan Assets	(48)	(288)
Defined Benefit Plan, Net Periodic Benefit Cost	42	(193)
Pension Benefits [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	0	0
Defined Benefit Plan, Interest Cost	25	29
Defined Benefit Plan, Expected Return on Plan Assets	(35)	(36)
Defined Benefit Plan, Amortization of Gains (Losses)	0	2
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0
Defined Benefit Plan, Net Periodic Benefit Cost	(10)	(5)
Other Benefits [Member] | CANADA
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	13	12
Defined Benefit Plan, Interest Cost	13	12
Defined Benefit Plan, Expected Return on Plan Assets	0	0
Defined Benefit Plan, Amortization of Gains (Losses)	0	0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0
Defined Benefit Plan, Other Costs	6	6
Defined Benefit Plan, Foreign Currency Exchange Rate Changes, Plan Assets	14	78
Defined Benefit Plan, Net Periodic Benefit Cost	46	108
Other Benefits [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Service Cost	34	46
Defined Benefit Plan, Interest Cost	31	44
Defined Benefit Plan, Expected Return on Plan Assets	0	0
Defined Benefit Plan, Amortization of Gains (Losses)	(50)	(13)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	0	0
Defined Benefit Plan, Net Periodic Benefit Cost	$ 15	$ 77