Summary Financial Information (Consolidated Statements of Cash Flows ) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Operating activities:
Net cash provided by (used for) operating activities	$ 60,450	$ 52,645	$ 38,254
Investing activities:
Proceeds from sales of marketable securities	12,336	5,869	6,919
Purchases of marketable securities	(1,571)	(4,311)	(3,689)
Capital expenditures	(14,368)	(22,320)	(17,243)
Other	0	0	(74)
Purchases of businesses, net of cash acquired		(182,467)	(19,992)
Net cash used for investing activities	(224,039)	(203,229)	(34,079)
Financing activities:
Proceeds from the issuance of common stock	50,439	242	1,607
Net borrowings (repayments) under lines of credit	(155,000)	154,057	0
Repayment of debt	(125,730)	(13,187)	(157,203)
Fees related to debt and equity offerings	(19,409)	0	(1,825)
Other	(1,265)	(897)	(859)
Net cash provided by (used for) financing activities	190,121	137,003	(48,387)
Effect of exchange rate changes on cash	(544)	2,128	(5,041)
Net change in cash and cash equivalents	25,988	(11,453)	(49,253)
Cash and cash equivalents at beginning of year	51,603	63,056	112,309
Cash and cash equivalents at end of year	$ 77,591	$ 51,603	$ 63,056