EARNINGS (LOSS) PER SHARE AND STOCKHOLDERS’ EQUITY: Narrative (Details) - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2019	Oct. 25, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount	945	29	669	69
Repurchase of stock (in shares)	2,100		2,100
Acquisition of treasury stock			$ 100,473,000	$ 45,766,000
Treasury stock, at cost	$ 1,881,954,000		1,881,954,000		$ 1,767,574,000
Accumulated other comprehensive income	$ 6,619,000		$ 6,619,000		$ 7,801,000
Common Stock Repurchase Program
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock repurchase program, authorized amount						$ 1,000,000,000.0
Repurchase of stock (in shares)	24,700		24,700
Treasury stock, at cost	$ 549,500,000		$ 549,500,000
Stock repurchase program, remaining amount	$ 450,500,000		$ 450,500,000