Fair Value Disclosures (Level 4 inventory fv) (Details 3) $ in Thousands	3 Months Ended							9 Months Ended		12 Months Ended
	Jul. 31, 2018 USD ($)	Apr. 30, 2018 USD ($)	Jan. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Jul. 31, 2017 USD ($)	Apr. 30, 2017 USD ($)	Jan. 31, 2017 USD ($)	Jul. 31, 2018 USD ($)	Jul. 31, 2017 USD ($)	Oct. 31, 2017 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Inventory Write-down	$ 11,061				$ 2,397			$ 28,746	$ 11,314
Operating communities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Inventory Write-down								26,126		$ 9,795
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Operating communities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of Operating Communities Tested (in ones)	55	65	64	51	53	46	57
Number of Communities Impaired (in ones)	5	4	5	1	4	6	2
Fair Value Of Communities Net Of Impairment Charges	$ 43,063	$ 21,811	$ 13,318	$ 6,982	$ 5,965	$ 25,092	$ 8,372	$ 43,063	$ 5,965	$ 6,982
Inventory Write-down	$ 9,065	$ 13,325	$ 3,736	$ 1,500	$ 1,360	$ 2,935	$ 4,000
North [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Operating communities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of Communities Impaired (in ones)		1
Inventory Write-down		$ 12,000
Mid-Atlantic [Member] | Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] | Operating communities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of Communities Impaired (in ones)	2
Inventory Write-down	$ 7,300