PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Components of net periodic benefit costs:
Stock Issued During Period, Value, Employee Benefit Plan	$ 50,000
Pension Plan [Member]
Components of net periodic benefit costs:
Service cost	577	$ 822	$ 1,758	$ 2,476
Interest cost	16,073	19,905	52,162	59,736
Expected return on plan assets	(35,210)	(37,065)	(106,566)	(111,246)
Amortization of prior service costs	(183)	(907)	(695)	(2,722)
Defined Benefit Plan, Amortization of Gain (Loss)	7,752	4,179	19,444	12,538
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	0	0	23,476	0
Defined Benefit Plan, Other Cost (Credit)	0	0	11,642	0
Net periodic benefit cost	(10,991)	(13,066)	1,221	(39,218)
Other postretirement
Components of net periodic benefit costs:
Service cost	0	57	62	170
Interest cost	41	1,010	1,519	3,029
Amortization of prior service costs	(1,276)	(1,164)	(3,596)	(3,491)
Defined Benefit Plan, Amortization of Gain (Loss)	(1,186)	(2,463)	(5,175)	(7,389)
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment	0	0	(49,491)	0
Net periodic benefit cost	$ (2,421)	$ (2,560)	(56,681)	$ (7,681)
TAS - Nashville, TN [Member]
Components of net periodic benefit costs:
Increase (Decrease) in Obligation, Other Postretirement Benefits			34,731
Increase (Decrease) in Obligation, Pension Benefits			4,898
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment			(8,363)
TAS - Grand Prairie, TX [Member]
Components of net periodic benefit costs:
Increase (Decrease) in Obligation, Other Postretirement Benefits			61,766
Defined Benefit Plan, Other Cost (Credit)			11,642
TAS - Grand Prairie, TX [Member] | Pension Plan [Member]
Components of net periodic benefit costs:
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment			(23,476)
TAS - Grand Prairie, TX [Member] | Other postretirement
Components of net periodic benefit costs:
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment			$ (41,128)