Pension Plan and Other Employee Benefits - Company's Target Asset Allocation Percentage, by Asset Class (Detail)	Feb. 28, 2018
Cash [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage	1.00%
Cash [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage	5.00%
Fixed Income [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage	35.00%
Fixed Income [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage	55.00%
Equity Securities [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage	45.00%
Equity Securities [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Target Allocation Percentage	60.00%