Pension and Other Post-retirement Benefit Plans (Details 1) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Pension
Amounts recognized in the Consolidated Balance Sheets
Current liability		$ (626)	$ (615)
Noncurrent liability		(38,233)	(32,154)
Amount recognized, end of year		(38,859)	(32,769)
Accumulated other comprehensive income (loss)
Net actuarial loss (gain)		21,408	9,269
Prior service cost		1,300	310
Accumulated other comprehensive (income) loss		22,708	9,579
Components of benefit costs (credit)
Net service cost		1,286	1,308	1,583
Interest cost		1,819	1,734	1,903
Expected return on plan assets		(480)	(454)	(656)
Amortization:
Actuarial (gain) loss		277	318	544
Prior service cost		17	4	20
Recurring activity		2,919	2,910	3,394
One time expense (income)	2,000	(19)	(32)	266
Net periodic benefit cost (credit)		2,900	2,878	3,660
Other Benefits
Amounts recognized in the Consolidated Balance Sheets
Current liability		(97)	(88)
Noncurrent liability		(749)	(697)
Amount recognized, end of year		(846)	(785)
Accumulated other comprehensive income (loss)
Net actuarial loss (gain)		(1,159)	(1,464)
Prior service cost		0	0
Accumulated other comprehensive (income) loss		(1,159)	(1,464)
Components of benefit costs (credit)
Net service cost		0	0	0
Interest cost		29	23	27
Expected return on plan assets		0	0	0
Amortization:
Actuarial (gain) loss		(187)	(259)	(322)
Prior service cost		0	0	0
Recurring activity		(158)	(236)	(295)
One time expense (income)		0	0	0
Net periodic benefit cost (credit)		$ (158)	$ (236)	$ (295)