Note 2 - Recent Accounting Pronouncements and Accounting Changes (Details Textual) - USD ($)	3 Months Ended
Jun. 30, 2017	Jun. 30, 2016
Payments Related to Tax Withholding for Share-based Compensation	$ 490,000	$ 0
Income Tax Expense (Benefit)	1,747,000	$ 2,252,000
Accounting Standards Update 2016-09 [Member]
Income Tax Expense (Benefit)	(545,000)
Accounting Standards Update 2016-09 [Member] \| Deferred Tax Assets [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	21,000
Accounting Standards Update 2016-09 [Member] \| Additional Paid-in Capital [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	60,000
Accounting Standards Update 2016-09 [Member] \| Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	(39,000)
Accounting Standards Update 2016-16 [Member] \| Income Tax Payable [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	1,100,000
Accounting Standards Update 2016-16 [Member] \| Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ (1,100,000)

Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a),(b)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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Amount of cash outflow to satisfy an employee's income tax withholding obligation as part of a net-share settlement of a share-based award.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 25
-Paragraph 19A
-URI http://asc.fasb.org/extlink&oid=96949009&loc=SL79513924-113897

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3291-108585

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