TOPIC 606 ADOPTION IMPACT AND REVENUE FROM CONTRACTS WITH CUSTOMERS: Narrative (Details) - USD ($)	9 Months Ended
	Dec. 31, 2018	Apr. 01, 2018	Mar. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ 1,715,066,000		$ 628,331,000
Capitalized contract cost, unamortized	9,500,000
Capitalized contract cost, net	3,000,000.0
Contract with customer, asset, credit loss expense	0
ASC 606 Adjustments | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings	$ (7,222,000)	$ 12,700,000