Income Taxes (Details) (USD $)	3 Months Ended	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2014	Aug. 31, 2013	Aug. 31, 2012
Income from continuing operations before income taxes [Abstract]
United States		$ 10,796,000	$ (196,289,000)	$ 54,304,000
Foreign		(61,000)	(141,160,000)	(11,348,000)
Income (loss) from continuing operations before income taxes		10,735,000	(337,449,000)	42,956,000
Current [Abstract]
Federal		5,927,000	556,000	5,267,000
State		229,000	356,000	453,000
Foreign		177,000	764,000	(2,000)
Total current tax expense (benefit)		6,333,000	1,676,000	5,718,000
Deferred [Abstract]
Federal		(4,911,000)	(58,194,000)	13,166,000
State		880,000	(264,000)	(2,748,000)
Foreign		(301,000)	(644,000)	(2,097,000)
Total deferred tax expense (benefit)		(4,332,000)	(59,102,000)	8,321,000
Total income tax expense (benefit)		2,001,000	(57,426,000)	14,039,000
Reconciliation of the difference between the federal statutory rate and the Company's effective tax rate [Abstract]
Federal statutory rate		35.00%	35.00%	35.00%
State taxes, net of credits		(7.10%)	1.20%	(5.70%)
Foreign income taxed at different rates		(8.10%)	(3.50%)	4.20%
Section 199 deduction		(6.90%)	0.50%	(0.30%)
Non-deductible officers’ compensation		2.70%	(0.10%)	1.50%
Noncontrolling interests		(12.10%)	0.20%	(2.20%)
Research and development credits		(1.00%)	0.20%	(2.00%)
Fixed asset tax basis adjustment		(21.30%)	0.00%	0.00%
Valuation allowance on deferred tax assets		21.80%	(8.60%)	0.00%
Unrecognized tax benefits		18.00%	0.00%	0.00%
Non-deductible goodwill		0.00%	(7.10%)	0.00%
Foreign interest income		0.00%	0.00%	0.70%
Other		(2.40%)	(0.80%)	1.50%
Effective tax rate		18.60%	17.00%	32.70%
Tax Benefit Recognized on Fixed Asset Adjustment in Tax Basis, Amount		2,000,000
Valuation Allowance, Deferred Tax Asset, Change in Amount	29,000,000	2,000,000	29,000,000
Deferred tax assets [Abstract]
Environmental liabilities	12,390,000	11,975,000	12,390,000
Employee benefit accruals	9,378,000	14,983,000	9,378,000
State income tax and other	2,478,000	3,096,000	2,478,000
Net operating loss carryforwards	11,758,000	11,357,000	11,758,000
State credit carryforwards	5,360,000	5,567,000	5,360,000
Inventory valuation methods	1,390,000	242,000	1,390,000
Amortizable goodwill and other intangibles	38,820,000	34,102,000	38,820,000
Valuation allowance	(29,696,000)	(32,086,000)	(29,696,000)
Total deferred tax assets	51,878,000	49,236,000	51,878,000
Deferred tax liabilities [Abstract]
Accelerated depreciation and basis differences	68,609,000	62,774,000	68,609,000
Prepaid expense acceleration	2,418,000	2,250,000	2,418,000
Foreign currency translation adjustment	30,000	93,000	30,000
Total deferred tax liabilities	71,057,000	65,117,000	71,057,000
Net deferred tax liability	19,179,000	15,881,000	19,179,000
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits, as of the beginning of the year		526,000	491,000	303,000
Additions for tax positions of prior years		1,000	0	0
Reductions for tax positions of prior years		0	(31,000)	(143,000)
Additions for tax positions of the current year		2,253,000	66,000	331,000
Unrecognized tax benefits, as of the end of the year	526,000	2,780,000	526,000	491,000
Foreign Country
Deferred tax liabilities [Abstract]
Operating Loss Carryforwards		$ 38,000,000
Foreign Country | Minimum
Deferred tax liabilities [Abstract]
Operating Loss Carryforwards, Expiration Dates		Aug. 31, 2015
Foreign Country | Maximum
Deferred tax liabilities [Abstract]
Operating Loss Carryforwards, Expiration Dates		Aug. 31, 2033
State and Local Jurisdiction | Minimum
Deferred tax liabilities [Abstract]
Tax Credit Carryforward, Expiration Date		Aug. 31, 2015
State and Local Jurisdiction | Maximum
Deferred tax liabilities [Abstract]
Tax Credit Carryforward, Expiration Date		Aug. 31, 2025