CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 174,138	$ 166,451
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	30,218	32,479
Amortization of intangible assets	10,653	6,618
Gain on investments in privately held companies	(550)	(547)
Loss on disposal of property, plant and equipment	7	0
Share-based compensation expense	33,239	26,354
Deferred income taxes	6,728	(473)
Change in fair value of contingent consideration for business acquisition	(4,908)	(9,925)
Changes in assets and liabilities, net of acquisitions:
Accounts receivable, net	(164,028)	(139,414)
Inventories	(5,692)	(15,194)
Other assets	(18,953)	(6,346)
Accounts payable	151,711	109,095
Accrued and other liabilities	43,521	71,549
Net cash provided by operating activities	256,084	240,647
Cash flows from investing activities:
Purchases of property, plant and equipment	(27,593)	(23,372)
Investment in privately held companies	(880)	(640)
Acquisitions, net of cash acquired	(88,323)	(66,987)
Proceeds from return of investment in privately held companies	237	0
Changes in restricted cash	0	715
Purchases of short-term investments	(6,789)	0
Sales of short-term investments	6,789	0
Purchases of trading investments	(2,842)	(5,868)
Proceeds from sales of trading investments	3,209	5,912
Net cash used in investing activities	(116,192)	(90,240)
Cash flows from financing activities:
Payment of cash dividends	(104,248)	(93,093)
Payment of contingent consideration for business acquisition	(5,000)	0
Purchases of registered shares	(20,408)	(63,764)
Proceeds from exercises of stock options and purchase rights	30,947	20,355
Tax withholdings related to net share settlements of restricted stock units	(25,505)	(13,054)
Net cash used in financing activities	(124,214)	(149,556)
Effect of exchange rate changes on cash and cash equivalents	1,677	(6,468)
Net increase (decrease) in cash and cash equivalents	17,355	(5,617)
Cash and cash equivalents, beginning of the period	547,533	519,195
Cash and cash equivalents, end of the period	564,888	513,578
Non-cash investing activities:
Property, plant and equipment purchased during the period and included in period end liability accounts	5,779	4,044
Unpaid purchase price for business acquisition	$ 1,000	$ 0