Consolidated Statements of Cash Flows (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net Earnings	$ 138,942	$ 118,244
Adjustments to Reconcile Net Earnings to Net Cash Provided by Operating Activities, Net of Effect of Non-Cash Activity -
Depreciation, Depletion and Amortization	62,176	59,253
Deferred Income Tax Provision	10,851	1,077
Stock Compensation Expense	7,559	7,235
Equity in Earnings of Unconsolidated Joint Venture	(19,424)	(21,831)
Distributions from Joint Venture	19,500	17,500
Changes in Operating Assets and Liabilities:
Accounts and Notes Receivable	(35,894)	(30,361)
Inventories	19,290	13,856
Accounts Payable and Accrued Liabilities	(24,399)	(14,905)
Other Assets	(3,551)	2,202
Income Taxes Payable (Receivable)	(174)	478
Net Cash Provided by Operating Activities	174,876	152,748
CASH FLOWS FROM INVESTING ACTIVITIES
Additions to Property, Plant, and Equipment	(93,444)	(44,851)
Acquisition Spending		(36,761)
Proceeds from Sale of Property, Plant, and Equipment	2,281
Net Cash Used in Investing Activities	(91,163)	(81,612)
CASH FLOWS FROM FINANCING ACTIVITIES
Increase (Decrease) in Credit Facility	10,000	(30,000)
Dividends Paid to Stockholders	(9,582)	(9,709)
Purchase and Retirement of Common Stock	(122,404)	(24,903)
Proceeds from Stock Option Exercises	1,992	20,426
Shares Redeemed to Settle Employee Taxes on Stock Compensation	(1,785)	(2,455)
Net Cash Used in Financing Activities	(121,779)	(46,641)
NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS AND RESTRICTED CASH	(38,066)	24,495
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AT BEGINNING OF PERIOD	48,068	6,561
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	$ 10,002	$ 31,056