Employee Retirement Benefits (Liability and Expense Reflected in the Balance Sheet and Income Statement) (Details) - USD ($) $ in Thousands	5 Months Ended		7 Months Ended		12 Months Ended
	Jan. 31, 2016		Aug. 31, 2015		Jan. 31, 2016		Jan. 31, 2015	Jan. 31, 2014
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Long-term portion in other liabilities	$ 7,662				$ 7,662		$ 11,812	$ 7,998
Other Postretirement Benefit Plan, Defined Benefit [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year			$ 12,125		12,125		8,254	8,307
Net periodic benefit cost					866		713	733
Other comprehensive (income) loss					(4,697)		3,391	(523)
Total recognized in net periodic benefit cost and other comprehensive income					(3,831)		4,104	210
Retiree benefits paid					(303)		(233)	(263)
Benefit obligation at end of year	7,991				7,991		12,125	8,254
Current portion in accrued liabilities	329				329		313	255
Long-term portion in other liabilities	$ 7,662				$ 7,662		$ 11,812	$ 7,999
Assumptions used to calculate benefit obligation:
Discount rate	4.25%				4.25%		3.50%	4.50%
Rate of compensation increase	4.00%				4.00%		4.00%	4.00%
Health care cost trend rate assumed for next year	6.83%	[1]	7.00%	[2]			7.20%	7.70%
Ultimate health care cost trend rate	4.50%	[1]	5.00%	[2]			5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2030	[1]	2025	[2]	2030	[1]	2025	2025
Assumptions used to calculated the net periodic benefit cost:
Discount rate	4.25%	[1]	3.50%	[2]			4.50%	4.25%
Rate of compensation increase					4.00%		4.00%	4.00%
Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates
Effect on total of service and interest cost components, one percentage point increase					$ 89
Effect on total of service and interest cost components, one percentage point decrease					(68)
Effect on accumulated postretirement benefit obligation, one percentage point increase					1,445
Effect on accumulated postretirement benefit obligation, one percentage point decrease					(1,129)
2017	$ 329				329
2018	350				350
2019	352				352
2020	347				347
2021-2025	$ 2,299				$ 2,299

[1] Assumptions used for the five months of fiscal 2016 following the August 31, 2015 remeasurement.

[2] Assumptions used for the seven months of fiscal 2016 prior to the plan amendment triggering the August 31, 2015 remeasurement.