Accumulated Other Comprehensive Income (Loss) - Summary of Amounts Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income applicable to common stock	[1]	$ (499)	$ (724)	$ (1,633)	$ (2,224)
Interest, net		(2,824)	(3,837)	(9,855)	(10,760)
Cost of Sales		361,635	366,413	1,075,705	1,123,324
Income Before Provision for Income Taxes		27,143	33,113	106,807	87,795
Tax benefit		(6,711)	(8,179)	(30,848)	(24,634)
Net Income		20,432	24,934	75,959	63,161
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amortization of defined benefit pension actuarial losses	[1],[2]	(794)	(1,149)	(2,598)	(3,538)
Defined Benefit Pension Plan Adjustments [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income applicable to common stock		(497)	(722)	(1,626)	(2,221)
Defined Benefit Pension Plan Adjustments [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Tax benefit	[1]	297	427	972	1,317
Income applicable to common stock	[1]	(497)	(722)	(1,626)	(2,221)
Cash Flow Hedge Adjustments [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Income Before Provision for Income Taxes	[1]	(4)	(4)	(13)	(9)
Tax benefit	[1]	2	2	6	6
Net Income	[1]	(2)	(2)	(7)	(3)
Cash Flow Hedge Adjustments [Member] | Interest rate contracts [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Interest, net	[1]	(7)	(6)	(20)	(16)
Cash Flow Hedge Adjustments [Member] | Commodity Contract [Member] | Amounts Reclassified From Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Cost of Sales	[1]	$ 3	$ 2	$ 7	$ 7

[1] Amounts in parentheses denote expense to statement of income.

[2] This component of accumulated other comprehensive income is included in the computation of net periodic benefit cost (see Note 8 for additional details).