Goodwill and Other Intangibles Goodwill and Intangible Asset Rollforward (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended	12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Mar. 31, 2012	Mar. 31, 2012	Mar. 31, 2011
Goodwill and Intangible Assets [Line Items]
Unamortizable Goodwill	$ 2,794	$ 2,794	$ 2,794	$ 2,794	$ 2,794
Gross balance					60,154
Amortizable Intangibles, Accumulated amortization					(18,949)
Net balance	35,865	41,205	39,984	41,205
Additions	22	206	615	615
Amortizable Intangibles, Amortization expense	(1,298)	(1,427)	(4,734)
Amortizable Intangibles, Net	31,795
Net balance	34,589	39,984	35,865	35,865
Customer Relationships Intangible [Member]
Goodwill and Intangible Assets [Line Items]
Weighted average remaining useful life in years				12 years 9 months
Amortizable Intangibles, Gross carrying amount					33,700
Amortizable Intangibles, Accumulated amortization					(9,899)
Amortizable Intangibles, Net	22,116	23,801	23,380	23,801
Amortizable Intangibles, Amortization expense	(421)	(421)	(1,264)
Amortizable Intangibles, Net	21,695	23,380	22,116	22,116
Production and Supply Contract Intangibles [Member]
Goodwill and Intangible Assets [Line Items]
Weighted average remaining useful life in years				3 years 9 months
Amortizable Intangibles, Gross carrying amount					7,893
Amortizable Intangibles, Accumulated amortization					(1,948)
Amortizable Intangibles, Net	4,850	5,945	5,701	5,945
Amortizable Intangibles, Amortization expense	(115)	(244)	(851)
Amortizable Intangibles, Net	4,735	5,701	4,850	4,850
Internally Developed Software Intangible [Member]
Goodwill and Intangible Assets [Line Items]
Weighted average remaining useful life in years				1 year 9 months
Amortizable Intangibles, Gross carrying amount					15,767
Amortizable Intangibles, Accumulated amortization					(7,102)
Amortizable Intangibles, Net	6,105	8,665	8,109	8,665
Additions	22	206	615	615
Amortizable Intangibles, Amortization expense	(762)	(762)	(2,619)
Amortizable Intangibles, Net	$ 5,365	$ 8,109	$ 6,105	$ 6,105