Goodwill And Other Intangible Assets (Other Intangibles) (Details) (USD $)	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	338,784,000	309,714,000
Accumulated Amortization	(111,960,000)	(95,510,000)
Net Carrying Amount	226,824,000	214,204,000
Intangible asset residual value	0
Estimated future amortization expense in 2014	26,600,000
Estimated future amortization expense in 2015	25,000,000
Estimated future amortization expense in 2016	23,400,000
Estimated future amortization expense in 2017	21,600,000
Estimated future amortization expense in 2018	19,800,000
Estimated future amortization expense thereafter	110,400,000
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	294,598,000	270,096,000
Accumulated Amortization	(91,354,000)	(74,253,000)
Net Carrying Amount	203,244,000	195,843,000
Non-competition agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	42,891,000	38,378,000
Accumulated Amortization	(19,338,000)	(20,427,000)
Net Carrying Amount	23,553,000	17,951,000
Other intangible assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,295,000	1,240,000
Accumulated Amortization	(1,268,000)	(830,000)
Net Carrying Amount	27,000	410,000
Weighted Average [Member] | Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years	15 years
Weighted Average [Member] | Non-competition agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	7 years	8 years
Minimum [Member] | Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	7 years
Maximum [Member] | Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	17 years