Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income	$ 62,995	$ 10,981
Adjustments to reconcile net income to cash provided by operating activities, net of the effects of acquisitions:
Depreciation and amortization	112,859	120,889
Loss on disposal of fixed assets	458	99
Deal-related compensation expense and accretion charges	114	114
Share-based compensation expense associated with equity awards	35,254	30,271
Deferred income taxes	(100,042)	(38,257)
Other gains (losses)	68	(371)
Changes in assets and liabilities
Accounts receivable and unbilled costs	47,439	(38,602)
Due from related party	554	24,679
Inventories	(1,222)	(2,543)
Prepaid expenses and other assets	29,324	7,587
Accounts payable	(5,378)	2,445
Accrued compensation and other expenses	(18,884)	2,926
Due to related party	(82)	(506)
Income taxes payable	(1,286)	(3,162)
Deferred revenue	(13,253)	14,285
Net cash provided by operating activities	148,918	130,835
Cash flows from investing activities:
Purchase of marketable securities	(71,323)	(135,737)
Proceeds from maturity of marketable securities	180,018	144,937
Purchase of fixed assets	(12,352)	(21,699)
Purchase of intangible assets	(505)	(1,022)
(Increase) decrease in deposits	(26)	22
Acquisition of businesses, net of cash acquired	(8,334)	(4,606)
Contingent purchase consideration	523	660
Collection of contingently returnable consideration from related party	0	12,864
Capitalized software development costs	(136)	(1,346)
Net cash provided by (used in) investing activities	87,865	(5,927)
Cash flows from financing activities:
Issuance of common stock under stock plans	1	2
Payment of contingent consideration	(660)	0
Treasury stock repurchases	(200,000)	(79,289)
Tax withholding on restricted stock units	(12,957)	(8,844)
Net cash used in financing activities	(213,616)	(88,131)
Effect of exchange rate changes on cash and cash equivalents	3,929	(1,995)
Net increase in cash and cash equivalents	27,096	34,782
Cash and cash equivalents and restricted cash, beginning of period	305,726	210,897
Cash and cash equivalents and restricted cash, end of period	332,822	245,679
Non-cash transactions:
Transfers of inventory to fixed assets	5,556	4,928
Additions to property, plant and equipment included in accounts payable	314	1,057
Issuance of common stock under employee stock plans	8,603	6,943
Contingent consideration related to acquisition, included in accrued other	$ 523	$ 660