Number of quarries distribution facilities and plants.

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- Definition

Number of states with aggregates business sales by destination.

+ References

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- Definition

Significant accounting policies.

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

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- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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- Definition

Amount of tax (expense) benefit, before reclassification adjustments, related to (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement benefit plans.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Topic 220

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-Section 45

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e640-108580

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Significant Accounting Policies - Additional Information (Detail) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($) Facility State Segment	Sep. 30, 2014 USD ($)	Dec. 31, 2014
Significant Accounting Policies [Line Items]
Number of quarries distribution facilities and plants	400
Number of states with aggregates business sales by destination \| State	26
Number of reportable segments \| Segment	3
Other comprehensive loss before reclassifications for pension and postretirement benefit plans, tax benefit \| $	$ 6,793	$ 280
Aggregates Product Line \| Product Concentration Risk \| Sales
Significant Accounting Policies [Line Items]
Total net sales, percentage			58.00%
Aggregates-Related Downstream Product Lines \| Product Concentration Risk \| Sales
Significant Accounting Policies [Line Items]
Total net sales, percentage			25.00%
Cement \| Product Concentration Risk \| Sales
Significant Accounting Policies [Line Items]
Total net sales, percentage			8.00%
Magnesia Specialties \| Product Concentration Risk \| Sales
Significant Accounting Policies [Line Items]
Total net sales, percentage			9.00%