LONG-TERM DEBT: (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Mar. 31, 2017
Debt Instrument [Line Items]
Total long-term debt and capital leases	$ 234,463	$ 230,612
Less current installments	2,089	39,819
Less deferred debt financing costs	4,329	1,552
Long-term debt, excluding current installments and deferred debt financing costs	228,045	189,241
Term loans
Debt Instrument [Line Items]
Total long-term debt and capital leases	0	155,000
Revolving credit facility
Debt Instrument [Line Items]
Total long-term debt and capital leases	230,000	70,000
Other debt and long-term liabilities
Debt Instrument [Line Items]
Total long-term debt and capital leases	$ 4,463	$ 5,612