Fair Value Disclosures (Level 4 Inv Impair inputs) (Details 2) - Operating communities [Member] $ in Thousands	3 Months Ended
	Oct. 31, 2017 USD ($) Homes_sold	Jul. 31, 2017 USD ($) Homes_sold	Apr. 30, 2017 USD ($) Homes_sold	Jan. 31, 2017 USD ($) Homes_sold	Oct. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Jan. 31, 2016 USD ($)
Minimum [Member]
Fair value inputs, assets, quantitative information [Line Items]
Average selling price	$ 467	$ 465	$ 827	$ 692	$ 0	$ 369	$ 0
Sales Pace	12	3	6	4	0	18	0
Fair Value Inputs, Discount Rate	16.40%	16.50%	16.30%	16.30%	0.00%	16.30%	0.00%
Maximum [Member]
Fair value inputs, assets, quantitative information [Line Items]
Average selling price	$ 540	$ 754	$ 856	$ 880	$ 0	$ 394	$ 0
Sales Pace	30	10	11	12	0	23	0
Fair Value Inputs, Discount Rate	16.40%	19.50%	16.30%	16.30%	0.00%	16.30%	0.00%