Summary Financial Information (Consolidated Statements of Cash Flows ) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Net Cash Provided By Used In Operating Activities [Abstract]
Net Cash Provided By Used In Operating Activities	$ 7,574	$ 4,418
Net Cash Provided By Used In Investing Activities [Abstract]
Purchase of marketable securities, net	1,165	(440)
Capital expenditures	(4,080)	(7,225)
Net Cash Provided By Used In Investing Activities	(1,433)	(6,376)
Proceeds from sale of businesses or assets	1,482	0
Net cash provided by investing activities from discontinued operations	0	409
Net Cash Provided By Used In Financing Activities [Abstract]
Net payments under lines-of-credit	(51)	(202)
Other	(180)	(242)
Net Cash Provided By Used In Financing Activities	(12)	1,289
Proceeds from exercise of stock options	219	1,733
Effect Of Exchange Rate On Cash And Cash Equivalents	(675)	(724)
Cash And Cash Equivalents Period Increase Decrease	5,454	(1,393)
Cash And Cash Equivalents At Carrying Value - Beginning of Period	89,473	80,139
Cash And Cash Equivalents At Carrying Value - End of Period	94,927	78,746
Parent Company [Member]
Net Cash Provided By Used In Operating Activities [Abstract]
Net Cash Provided By Used In Operating Activities	6,557	5,597
Net Cash Provided By Used In Investing Activities [Abstract]
Purchase of marketable securities, net	0	0
Capital expenditures	(3,354)	(6,006)
Net Cash Provided By Used In Investing Activities	(3,354)	(5,597)
Net cash provided by investing activities from discontinued operations		409
Net Cash Provided By Used In Financing Activities [Abstract]
Net payments under lines-of-credit		0
Other	213	217
Net Cash Provided By Used In Financing Activities	432	1,950
Proceeds from exercise of stock options	219	1,733
Effect Of Exchange Rate On Cash And Cash Equivalents	0	0
Cash And Cash Equivalents Period Increase Decrease	3,635	1,950
Cash And Cash Equivalents At Carrying Value - Beginning of Period	55,958	45,954
Cash And Cash Equivalents At Carrying Value - End of Period	59,593	47,904
Guarantor Subsidiaries [Member]
Net Cash Provided By Used In Operating Activities [Abstract]
Net Cash Provided By Used In Operating Activities	(1,276)	569
Net Cash Provided By Used In Investing Activities [Abstract]
Purchase of marketable securities, net		0
Capital expenditures	(211)	(454)
Net Cash Provided By Used In Investing Activities	1,271	(454)
Proceeds from sale of businesses or assets	1,482
Net Cash Provided By Used In Financing Activities [Abstract]
Net payments under lines-of-credit		0
Other	0	(116)
Net Cash Provided By Used In Financing Activities	0	(116)
Effect Of Exchange Rate On Cash And Cash Equivalents	0	0
Cash And Cash Equivalents Period Increase Decrease	(5)	(1)
Cash And Cash Equivalents At Carrying Value - Beginning of Period	5	7
Cash And Cash Equivalents At Carrying Value - End of Period	0	6
Non-Guarantor Subsidiaries [Member]
Net Cash Provided By Used In Operating Activities [Abstract]
Net Cash Provided By Used In Operating Activities	2,293	(1,748)
Net Cash Provided By Used In Investing Activities [Abstract]
Purchase of marketable securities, net	1,165	(440)
Capital expenditures	(515)	(765)
Net Cash Provided By Used In Investing Activities	650	(325)
Net Cash Provided By Used In Financing Activities [Abstract]
Net payments under lines-of-credit	(51)	(202)
Other	(393)	(343)
Net Cash Provided By Used In Financing Activities	(444)	(545)
Effect Of Exchange Rate On Cash And Cash Equivalents	(675)	(724)
Cash And Cash Equivalents Period Increase Decrease	1,824	(3,342)
Cash And Cash Equivalents At Carrying Value - Beginning of Period	33,510	34,178
Cash And Cash Equivalents At Carrying Value - End of Period	35,334	30,836
Consolidation, Eliminations [Member]
Net Cash Provided By Used In Operating Activities [Abstract]
Net Cash Provided By Used In Operating Activities	0
Net Cash Provided By Used In Financing Activities [Abstract]
Other	0
Net Cash Provided By Used In Financing Activities	0
Effect Of Exchange Rate On Cash And Cash Equivalents	$ 0