CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
OPERATING ACTIVITIES
Net income	$ 276,142	$ 264,308	$ 114,394
Reconciliation of net income to net cash provided by (used in) operating activities:
Depreciation, amortization and accretion	38,912	44,941	48,572
Loss on extinguishment of debt	0	447	0
Bad debt expense	3,498	2,849	4,168
Deferred tax expense	2,934	6,939	8,138
Stock-based compensation	14,477	14,774	14,306
Excess tax benefit from stock-based compensation	(1,953)	(546)	(1,982)
Loss on disposal of property and equipment	698	277	387
Impairment of operating lease assets and other long-lived assets	1,365	180	2,417
Restructuring charges	0	295	1,667
Gain on settlement of asset retirement obligations	(705)	0	0
Changes in operating assets and liabilities:
Trade accounts receivable, net	(10,493)	(16,157)	10,770
Inventories, net	(32,777)	8,827	(751)
Prepaid expenses and other current assets	2,477	(515)	11,124
Income tax receivable	(5,811)	(165)	26,999
Net operating lease assets and liabilities	(3,264)
Other assets	(6,558)	2,630	(1,714)
Trade accounts payable	23,312	26,667	(4,462)
Other accrued expenses	(11,112)	(2,792)	30,904
Income taxes payable	(6,226)	4,355	290
Long-term liabilities	1,418	2,191	62,128
Net cash (used in) provided by operating activities	286,334	359,505	327,355
INVESTING ACTIVITIES
Purchases of property and equipment	(32,455)	(29,086)	(34,813)
Proceeds from sales of property and equipment	491	68	116
Net cash used in investing activities	(31,964)	(29,018)	(34,697)
FINANCING ACTIVITIES
Proceeds from short-term borrowings	69,336	162,001	214,751
Repayments of short-term borrowings	(69,197)	(161,621)	(214,889)
Debt issuance costs on short-term borrowings	0	(1,297)	0
Proceeds on issuance of stock for employee stock purchase plan	1,288	1,025	765
Proceeds from exercise of options	3,615	0	0
Repurchases of common stock	(190,405)	(161,395)	(149,687)
Cash paid for shares withheld for taxes	(6,148)	(5,328)	(8,105)
Repayment of mortgage principal	(603)	(578)	(550)
Net cash used in financing activities	(192,114)	(167,193)	(157,715)
Effect of foreign currency exchange rates on cash and cash equivalents	(2,512)	(3,572)	3,263
Net change in cash and cash equivalents	59,744	159,722	138,206
Cash and cash equivalents at beginning of period	589,692	429,970	291,764
Cash and cash equivalents at end of period	649,436	589,692	429,970
Cash paid during the period
Income taxes, net of refunds of $5,389, $3,824, and $23,133, as of March 31, 2020, 2019, and 2018, respectively	74,573	53,657	14,407
Interest	2,466	3,811	3,774
Operating leases	61,120
Non-cash investing and financing activities:
Accrued for purchases of property and equipment	1,171	1,789	2,020
Accrued for asset retirement obligations	224	4,706	1,359
Accrued for shares withheld for taxes	$ 0	$ 0	$ 171