CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
OPERATING ACTIVITIES
Net income	$ 349,117	$ 260,052
Reconciliation of net income to net cash used in operating activities:
Depreciation, amortization, and accretion	30,637	29,437
Amortization on cloud computing arrangements	420	0
Bad debt expense	6,392	693
Deferred tax expense (benefit)	1,859	(1,020)
Stock-based compensation	17,559	12,766
Excess tax benefit from stock-based compensation	(1,687)	(1,755)
Loss on disposal of property and equipment	259	679
Impairment of operating lease assets and other long-lived assets	4,060	1,382
Gain on settlement of asset retirement obligations	(207)	0
Changes in operating assets and liabilities:
Trade accounts receivable, net	(133,708)	(108,982)
Inventories, net	6,321	(87,104)
Prepaid expenses and other current assets	(32,387)	(19,970)
Income tax receivable	(2,305)	(5,781)
Net operating lease assets and liabilities	1,652	(1,692)
Other assets	(3,023)	(5,924)
Trade accounts payable	152,797	119,794
Other accrued expenses	75,658	21,504
Income taxes payable	47,530	23,545
Long-term liabilities	1,318	1,101
Net cash provided by operating activities	522,262	238,725
INVESTING ACTIVITIES
Purchases of property and equipment	(21,300)	(23,664)
Proceeds from sales of property and equipment	49	266
Net cash used in investing activities	(21,251)	(23,398)
FINANCING ACTIVITIES
Proceeds from short-term borrowings	9,100	69,336
Repayments of short-term borrowings	(9,478)	(63,178)
Proceeds from issuance of stock	698	618
Proceeds from exercise of stock options	5,583	3,145
Repurchases of common stock	0	(190,405)
Cash paid for shares withheld for taxes	(7,203)	(5,995)
Repayments of mortgage principal	(470)	(448)
Net cash used in financing activities	(1,770)	(186,927)
Effect of foreign currency exchange rates on cash and cash equivalents	7,879	(1,228)
Net change in cash and cash equivalents	507,120	27,172
Cash and cash equivalents at beginning of period	649,436	589,692
Cash and cash equivalents at end of period	1,156,556	616,864
Cash paid during the period
Income taxes, net of refunds of $1,489 and $5,302, as of December 31, 2020 and 2019, respectively	56,957	47,482
Interest	2,336	1,749
Operating leases	43,263	45,732
Non-cash investing activities
Accrued for purchases of property and equipment	1,900	1,444
Accrued for asset retirement obligations	$ 1,595	$ 38