Interest on Borrowings (Table Text Block)	12 Months Ended
	Mar. 31, 2020
Interest Expense, Borrowings [Abstract]
Components of interest expense	Years Ended March 31,     2020   2019   2018     (In thousands) Interest expense $ 180,444 $ 150,609 $ 125,412 Capitalized interest   (23,517)   (12,733)   (6,466) Amortization of transaction costs   4,427   3,745   3,867 Interest expense resulting from cash flow hedges   (404)   824   3,893 Total interest expense   160,950   142,445   126,706
Interest rates and company borrowings	Revolving Credit Activity       Years Ended March 31,       2020   2019   2018       (In thousands, except interest rates)   Weighted average interest rate during the year   3.31 % 3.39 % 2.48 % Interest rate at year end   2.86 % 3.60 % 2.84 % Maximum amount outstanding during the year $ 1,086,000 $ 959,400 $ 538,000   Average amount outstanding during the year $ 1,002,081 $ 699,415 $ 517,997   Facility fees $ 193 $ 374 $ 410