LONG-TERM DEBT: (Details) (USD $)	3 Months Ended			3 Months Ended		3 Months Ended			3 Months Ended				3 Months Ended						3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Mar. 31, 2014	Jun. 30, 2014 Interest Rate Swap [Member] Derivative Agreement 20140310 [Member] Cash Flow Hedging [Member]	Mar. 10, 2014 Interest Rate Swap [Member] Derivative Agreement 20140310 [Member] Cash Flow Hedging [Member]	Jun. 30, 2014 London Interbank Offered Rate (LIBOR) [Member] Interest Rate Swap [Member] Derivative Agreement 20140310 [Member]	Jun. 30, 2014 Term Loan [Member]	Mar. 31, 2014 Term Loan [Member]	Jun. 30, 2014 Term Loan [Member] Debt Instrument Quarterly Installments Payable through September 2014 [Member]	Jun. 30, 2014 Term Loan [Member] Debt Instrument Quarterly Installments Payable through September 2017 [Member]	Jun. 30, 2014 Term Loan [Member] Debt Instrument Quarterly Installments Payable through June 2018 [Member]	Jun. 30, 2014 Term Loan [Member] Debt Instrument Final Installments Payable on 9 October 2018 [Member]	Jun. 30, 2014 Term Loan [Member] London Interbank Offered Rate (LIBOR) [Member]	Jun. 30, 2014 Capital Lease and Installment Obligations [Member]	Mar. 31, 2014 Capital Lease and Installment Obligations [Member]	Jun. 30, 2014 Other Debt and Long Term Liabilities [Member]	Mar. 31, 2014 Other Debt and Long Term Liabilities [Member]	Jun. 30, 2014 Revolving Credit Facility [Member]	Jun. 30, 2014 Revolving Credit Facility [Member] London Interbank Offered Rate (LIBOR) [Member]
Long-term debt
Total long-term debt and capital leases	$ 310,343,000		$ 317,610,000				$ 288,750,000	$ 292,500,000						$ 9,989,000	$ 12,990,000	$ 11,604,000	$ 12,120,000
Less current installments	31,368,000		28,567,000
Long-term debt, excluding current installments	278,975,000		289,043,000
Existing debt repaid with proceeds of term loan	5,502,000	4,890,000
Aggregate amount of borrowing commitment							300,000,000
Required quarterly installment payments									3,800,000	7,500,000	11,300,000
Final payment of long-term debt												161,300,000
Long-term debt variable interest rate description						LIBOR
Long-term debt basis spread on variable interest rate (as a percent)													2.00%						2.00%
Weighted-average interest rate on long-term debt (as a percent)	2.30%
Outstanding revolving credit borrowings																		0
Outstanding letters of credit	2,200,000
Revolving credit facility dividend restrictions amount, maximum																		30,000,000
Fixed interest rate payable on swap (as a percent)					0.98%
Notional amount of derivative					50,000,000
LIBOR rate (as a percent)	0.23%
Fair market value of the derivative				0
Unrealized loss of the derivative recorded in other comprehensive income (loss)				$ 200,000