Note 17 - Business Segments (Detail) - Segments’ Revenues, Gross Profit And Income (Loss) Before Income Taxes And Earnings (USD $)
In Thousands, unless otherwise specified
 3 Months Ended
Nov. 30, 2011
Nov. 30, 2010
Revenues:    
Revenues $ 1,517,603 $ 1,543,282
Gross profit:    
Gross Profit 119,942 61,604
Selling, general and administrative expenses:    
Selling, general and administrative expenses 69,477 70,895
Income (loss) before income taxes and earnings from unconsolidated entities:    
Income (loss) before income taxes and earnings (losses) from unconsolidated entities 68,382 (29,849)
Power [Member]
    
Revenues:    
Revenues 494,700 505,000
Gross profit:    
Gross Profit 27,000 (29,500)
Gross profit percentage:    
Gross Profit Percentage 5.50% (5.80%)
Selling, general and administrative expenses:    
Selling, general and administrative expenses 9,700 11,600
Income (loss) before income taxes and earnings from unconsolidated entities:    
Income (loss) before income taxes and earnings (losses) from unconsolidated entities 17,600 (41,200)
Plant Services [Member]
    
Revenues:    
Revenues 295,100 257,800
Gross profit:    
Gross Profit 23,000 23,300
Gross profit percentage:    
Gross Profit Percentage 7.80% 9.00%
Selling, general and administrative expenses:    
Selling, general and administrative expenses 2,500 2,100
Income (loss) before income taxes and earnings from unconsolidated entities:    
Income (loss) before income taxes and earnings (losses) from unconsolidated entities 20,500 21,200
E&I [Member]
    
Revenues:    
Revenues 459,400 518,600
Gross profit:    
Gross Profit 37,700 48,400
Gross profit percentage:    
Gross Profit Percentage 8.20% 9.30%
Selling, general and administrative expenses:    
Selling, general and administrative expenses 18,400 18,200
Income (loss) before income taxes and earnings from unconsolidated entities:    
Income (loss) before income taxes and earnings (losses) from unconsolidated entities 19,600 30,800
E&C [Member]
    
Revenues:    
Revenues 163,100 178,300
Gross profit:    
Gross Profit 15,300 6,300
Gross profit percentage:    
Gross Profit Percentage 9.40% 3.50%
Selling, general and administrative expenses:    
Selling, general and administrative expenses 12,100 12,700
Income (loss) before income taxes and earnings from unconsolidated entities:    
Income (loss) before income taxes and earnings (losses) from unconsolidated entities 4,600 (5,000)
F&M [Member]
    
Revenues:    
Revenues 105,300 83,600
Gross profit:    
Gross Profit 16,500 12,100
Gross profit percentage:    
Gross Profit Percentage 15.70% 14.50%
Selling, general and administrative expenses:    
Selling, general and administrative expenses 9,200 7,700
Income (loss) before income taxes and earnings from unconsolidated entities:    
Income (loss) before income taxes and earnings (losses) from unconsolidated entities 8,500 4,200
Corporate [Member]
    
Revenues:    
Revenues 0 0
Gross profit:    
Gross Profit 400 1,000
Selling, general and administrative expenses:    
Selling, general and administrative expenses 17,400 18,500
Income (loss) before income taxes and earnings from unconsolidated entities:    
Income (loss) before income taxes and earnings (losses) from unconsolidated entities (17,000) (16,800)
Total [Member]
    
Revenues:    
Revenues 1,517,600 1,543,300
Gross profit:    
Gross Profit 119,900 61,600
Gross profit percentage:    
Gross Profit Percentage 7.90% 4.00%
Selling, general and administrative expenses:    
Selling, general and administrative expenses 69,500 70,900
Income (loss) before income taxes and earnings from unconsolidated entities:    
Income (loss) before income taxes and earnings (losses) from unconsolidated entities 68,400 (29,800)
Westinghouse [Member]
    
Selling, general and administrative expenses:    
Selling, general and administrative expenses 200 100
Income (loss) before income taxes and earnings from unconsolidated entities:    
Income (loss) before income taxes and earnings (losses) from unconsolidated entities $ 14,600 $ (23,000)