Employee Postretirement Benefits Employee Postretirement Benefits (Tables)

9 Months Ended

Oct. 31, 2015

Oct. 31, 2014

Compensation and Retirement Disclosure [Abstract]

Schedule of Accumulated and Projected Benefit Obligations

The effect of the August 31, 2015 remeasurement of the benefit obligation is as follows:

Benefit obligation at January 31, 2015	$	12,125
Service cost	252
Interest cost	244
Prior service (credit) due to plan amendment	(958		)
Actuarial (gain) due to assumption changes	(3,403		)
Retiree benefits paid	(89		)
Benefit obligation at August 31, 2015	$	8,171
Fair value of plan assets	—
Funded status at August 31, 2015	$	(8,171	)
Net actuarial loss in accumulated other comprehensive income	2,710
Unrecognized prior service (credit)	(958		)
Accrued postretirement benefit cost at August 31, 2015	$	(6,419	)

Schedule of Assumptions Used

The assumptions used to measure the benefit obligation were as follows:

Assumptions used to calculate benefit obligation:
Measurement date	August 31, 2015		January 31, 2015
Discount rate	4.25	%	3.50	%
Wage inflation rate	4.00	%	4.00	%
Average remaining years of service	15.14		16.05
Health care cost trend rates:
Health care cost trend rate assumed for next year	7.00	%	7.20	%
Ultimate health care cost trend rate	4.50	%	5.00	%
Year that the rate reaches the ultimate trend rate	2030		2025

Components of net periodic benefit cost for postretirement plan

The components of the net periodic benefit cost for postretirement benefits are as follows:

	Three Months Ended				Nine Months Ended
	October 31, 2015		October 31, 2014		October 31, 2015		October 31, 2014
Service cost	$	49	$	49	$	265	$	147
Interest cost	92		91		302		274
Amortization of actuarial losses	38		38		206		114
Net periodic benefit cost	$	179	$	178	$	773	$	535