Postretirement Medical Benefits (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Number of former union employees not covered under plan	64
Reduction in accumulated postretirement benefit obligation as result of modifications	$ 14,400,000
Curtailment gain included within selling, general and administrative expenses	3,600,000
Discount rate assumptions used for remeasurement of costs and benefit obligation (in hundredths)	4.90%	4.00%	4.55%
Change in benefit obligation [Roll Forward]
Benefit obligation at beginning of year	4,725,000	4,082,000
Service cost	180,000	130,000	111,000
Interest cost	235,000	186,000	181,000
Actuarial loss (gain)	521,000	327,000
Benefit obligation at end of year	5,661,000	4,725,000	4,082,000
Unfunded status of the plans	(5,661,000)	(4,725,000)
Amounts recognized in the balance sheet [Abstract]
Accrued postretirement benefit liabilities	5,661,000	4,725,000
Accumulated other comprehensive loss (pre-tax) related to [Abstract]
Unrecognized net actuarial losses (gains)	1,342,000	1,510,000
Unrecognized prior service cost (credit)	0	(28,000)
Estimated net loss expected to be amortized from accumulated other comprehensive income	2,100,000
Prior service cost (credit) expected to be amortized from accumulated other comprehensive income	(3,000,000)
Net Periodic benefit costs related to retirement plans [Abstract]
Service cost	180,000	130,000	111,000
Interest cost	235,000	186,000	181,000
Amortization of prior service cost	28,000	110,000	111,000
Amortization of net actuarial loss	690,000	261,000	173,000
Total net periodic benefit costs	1,133,000	687,000	576,000
Actuarial assumptions used to determine costs and benefit obligations related to postretirement plan [Abstract]
Discount rate (in hundredths)	4.90%	4.00%	4.55%
Summary of expected future benefit payments [Abstract]
2013	0
2014	5,677,000
2015	0
2016	0
2017	0
Years 2018 - 2022	0
One-percentage-point change in assumed health care cost trend rates [Abstract]
Effect on total of service and interest cost components, 1-Percentage-Point Increase	1,000
Effect on total of service and interest cost components, 1-Percentage-Point Decrease	(1,000)
Effect on postretirement benefit obligation, 1-Percentage-Point Increase	31,000
Effect on postretirement benefit obligation, 1-Percentage-Point Decrease	(30,000)
Postretirement Benefits [Member]
Net Periodic benefit costs related to retirement plans [Abstract]
Total net periodic benefit costs	(1,874,000)	(1,969,000)	(7,329,000)
Summary of expected future benefit payments [Abstract]
2013	2,064,000
2014	1,219,000
2015	1,453,000
2016	67,000
2017	60,000
Years 2018 - 2022	213,000
U.S. Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate assumptions used for remeasurement of costs and benefit obligation (in hundredths)	0.45%	0.55%	1.30%	1.87%
Change in benefit obligation [Roll Forward]
Benefit obligation at beginning of year	5,950,000	6,955,000
Service cost	1,000	4,000	69,000
Interest cost	33,000	81,000	527,000
Benefits paid	(850,000)	(751,000)
Actuarial loss (gain)	(174,000)	(339,000)
Translation adjustment	0	0
Benefit obligation at end of year	4,960,000	5,950,000	6,955,000
Unfunded status of the plans	(4,960,000)	(5,950,000)
Amounts recognized in the balance sheet [Abstract]
Accrued postretirement benefit liabilities	4,960,000	5,950,000
Accumulated other comprehensive loss (pre-tax) related to [Abstract]
Unrecognized net actuarial losses (gains)	5,087,000	7,809,000
Unrecognized prior service cost (credit)	(2,888,000)	(7,094,000)
Net Periodic benefit costs related to retirement plans [Abstract]
Service cost	1,000	4,000	69,000
Interest cost	33,000	81,000	527,000
Amortization of prior service cost	(4,206,000)	(4,752,000)	(6,433,000)
Amortization of unrecognized loss	2,548,000	2,887,000	2,246,000
Curtailment gain	0	0	(3,495,000)
Total net periodic benefit costs	(1,624,000)	(1,780,000)	(7,086,000)
Actuarial assumptions used to determine costs and benefit obligations related to postretirement plan [Abstract]
Discount rate (in hundredths)	0.45%	0.55%	1.30%	1.87%
Canadian Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate assumptions used for remeasurement of costs and benefit obligation (in hundredths)	3.50%	3.00%	3.00%	3.75%
Change in benefit obligation [Roll Forward]
Benefit obligation at beginning of year	156,000	192,000
Service cost	0	0	7,000
Interest cost	5,000	5,000	23,000
Benefits paid	(21,000)	(24,000)
Actuarial loss (gain)	(4,000)	(21,000)
Translation adjustment	(10,000)	4,000
Benefit obligation at end of year	126,000	156,000	192,000
Unfunded status of the plans	(126,000)	(156,000)
Amounts recognized in the balance sheet [Abstract]
Accrued postretirement benefit liabilities	126,000	156,000
Accumulated other comprehensive loss (pre-tax) related to [Abstract]
Unrecognized net actuarial losses (gains)	(129,000)	(254,000)
Unrecognized prior service cost (credit)	(335,000)	(504,000)
Net Periodic benefit costs related to retirement plans [Abstract]
Service cost	0	0	7,000
Interest cost	5,000	5,000	23,000
Amortization of transition obligation	0	0	2,000
Amortization of prior service cost	(140,000)	(142,000)	(80,000)
Amortization of net actuarial loss	(115,000)	(52,000)	(43,000)
Curtailment gain	0	0	(152,000)
Total net periodic benefit costs	$ (250,000)	$ (189,000)	$ (243,000)
Actuarial assumptions used to determine costs and benefit obligations related to postretirement plan [Abstract]
Discount rate (in hundredths)	3.50%	3.00%	3.00%	3.75%
Current medical cost trend rate (in hundredths)	7.14%	8.57%	9.29%
Ultimate medical cost trend rate (in hundredths)	5.00%	5.00%	5.00%
Year trend rate declines to ultimate	2017	2017	2017