STOCKHOLDERS' EQUITY: - Narrative (Details) - USD ($)	12 Months Ended			79 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2018	Aug. 29, 2011
Authorized shares and par value disclosure
Common stock, authorized shares	200,000,000	200,000,000.0	200,000,000.0	200,000,000
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10	$ 0.10	$ 0.10
Preferred stock, authorized shares	1,000,000			1,000,000
Preferred stock, par value (in dollars per share)	$ 1.00			$ 1.00
Stockholders' Equity
Number of warrants outstanding (in shares)	4,942			4,942
Warrants exercise price (in dollars per share)	$ 13.24			$ 13.24
Repurchase of treasury stock	$ 88,884,000	$ 30,542,000	$ 52,764,000
Dividends paid on common stock	$ 0	$ 0	$ 0
Common stock repurchase program
Stockholders' Equity
Maximum amount of common stock that may be repurchased					$ 500,000,000
Number of shares repurchased	3,300,000	1,300,000	2,600,000	20,100,000
Repurchase of treasury stock	$ 88,900,000	$ 30,500,000	$ 52,800,000	$ 374,600,000
Remaining capacity under the stock repurchase program	$ 125,400,000			$ 125,400,000