LONG-TERM DEBT: (Details) (USD $)			0 Months Ended	12 Months Ended		12 Months Ended		12 Months Ended							12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Jul. 25, 2012 Interest rate swap July 25, 2011 derivative agreement	Mar. 31, 2013 Interest rate swap July 25, 2011 derivative agreement	Jul. 25, 2011 Interest rate swap July 25, 2011 derivative agreement	Mar. 31, 2013 Term loan credit agreement	Mar. 31, 2012 Term loan credit agreement	Mar. 31, 2013 Term loan credit agreement LIBOR	Mar. 31, 2013 Capital leases and installment payment obligations	Mar. 31, 2012 Capital leases and installment payment obligations	Mar. 31, 2013 Other debt and long-term liabilities	Mar. 31, 2012 Other debt and long-term liabilities	Mar. 31, 2013 Revolving credit facility	Mar. 31, 2012 Revolving credit facility	Mar. 31, 2013 Revolving credit facility LIBOR	Mar. 31, 2013 Revolving credit facility Alternative base rate	Mar. 31, 2013 Revolving credit facility Federal Funds rate
Long-term debt
Total long-term debt and capital leases	$ 253,505,000	$ 278,222,000				$ 218,000,000	$ 224,000,000		$ 21,368,000	$ 35,726,000	$ 14,137,000	$ 18,496,000
Less current installments	16,105,000	26,336,000
Long-term debt, excluding current installments	237,400,000	251,886,000
Long-term debt stated interest rate percentage, minimum									3.00%	3.00%
Long-term debt stated interest rate percentage, maximum									8.00%	8.00%
Maximum remaining maturity period of debt									9 years	9 years
Aggregate amount of borrowing commitment						600,000,000							120,000,000
Required quarterly installment payments						1,500,000
Final payment of long-term debt due March 15, 2015						207,500,000
Long-term debt variable interest rate description								LIBOR							LIBOR	Alternative base rate	Federal Funds rate
Long-term debt basis spread on variable interest rate (as a percent)								3.00%							2.75%
Weighted-average interest rate on long-term debt (as a percent)						3.70%
Outstanding letters of credit													2,200,000
Outstanding revolving credit borrowings													0	0
Revolving credit facility dividend restrictions amount, maximum													30,000,000
Fixed interest rate payable on swap (as a percent)					0.94%
Notional amount of derivative					150,000,000
Description of variable interest rate basis receivable on swap			LIBOR
LIBOR rate (as a percent)				0.30%
Fair market value of the derivative					0
Unrealized loss of the derivative recorded in other comprehensive income (loss)				$ 800,000