1. Summary of patient service revenues (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Sources of patient service revenues	$ 97,072	$ 138,491	$ 334,592	$ 229,238
Medicare
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Sources of patient service revenues	24,196	22,728	47,582	48,592
Medicaid
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Sources of patient service revenues	35,610	61,732	196,789	82,997
Managed Care
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Sources of patient service revenues	26,827	33,016	56,203	61,134
Indemnity Self Pay And Other
Health Care Organization, Receivable and Revenue Disclosures [Line Items]
Sources of patient service revenues	$ 10,439	$ 21,015	$ 34,018	$ 36,515