Industry Segment Information (Schedule Of Segment Reporting Information By Segment) (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Nov. 30, 2015 USD ($) segment	Nov. 30, 2014 USD ($)	Aug. 31, 2012 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Total operating revenues	$ 121,622	$ 134,845
Segment operating income	11,748	11,902
Unallocated general and administrative expenses	(9,015)	(12,871)
Earnings before income taxes	10,396	11,661
Capital Expenditures	4,705	3,649
Depreciation and Amortization	4,295	3,748
Environmental remediation expenses	0		$ 7,200
Operating Segments [Member]
Segment Reporting Information [Line Items]
Segment operating income	15,774	16,913
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Unallocated general and administrative expenses	(4,026)	(5,011)
Interest and other expense, net	$ (1,352)	(241)
Irrigation [Member]
Segment Reporting Information [Line Items]
Number of operating segments | segment	5
Total operating revenues	$ 101,327	114,716
Segment operating income	12,692	14,669
Capital Expenditures	3,152	3,084
Depreciation and Amortization	$ 3,094	2,486
Environmental remediation expenses		1,300
Infrastructure [Member]
Segment Reporting Information [Line Items]
Number of operating segments | segment	1
Total operating revenues	$ 20,295	20,129
Segment operating income	3,082	2,244
Capital Expenditures	1,553	565
Depreciation and Amortization	$ 1,201	1,262
Environmental remediation expenses		$ 200