Loans Payable, Senior Notes and Mortgage Company Loan Facility Credit Facility (Details Textual 2) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Oct. 31, 2016	Jul. 31, 2016	May 19, 2016	Oct. 31, 2015	Aug. 01, 2013
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 1,457,196
Long-term Line of Credit		$ 1,184,758
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity					$ 1,035,000
Line of Credit Facility, term of contract		5 years
Line of Credit Facility, Expiration Date		Aug. 01, 2018
Long-term Line of Credit		$ 450,000		$ 350,000
Letters of Credit Outstanding, Amount		$ 80,000
Debt Instrument, Interest Rate at Period End		1.97%
May 2016 Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity		$ 1,295,000	$ 1,215,000
Line of Credit Facility, term of contract		5 years
Line of Credit Facility, Expiration Date		May 19, 2021
Maximum Permissible Leverage Ratio		175.00%
Minimum Net Worth Required for Compliance		$ 2,610,000
Existing Leverage Ratio		.8383
Tangible Net Worth		$ 4,120,000
Ability to repurchase common stock		$ 2,140,000
Guarantor Subsidiaries [Member]
Line of Credit Facility [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent		100.00%
Subsequent Event [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Repayments of Lines of Credit	$ 100,000