Significant Accounting Policies (Policies)	9 Months Ended
Significant Accounting Policies (Policies)	Dec. 31, 2016
Accounting Policies [Abstract]
Basis of Accounting, Policy [Policy Text Block]	Basis of Presentation The accompanying condensed consolidated balance sheet as of March 31, 2016, has been derived from audited consolidated financial statements. The accompanying unaudited interim condensed consolidated financial statements have been prepared on the same basis as our annual audited consolidated financial statements and in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and the rules and regulations of the Securities and Exchange Commission (“SEC”) for interim financial statements. In the opinion of management, such unaudited information includes all adjustments (consisting only of normal recurring accruals) necessary for a fair presentation of this interim information. Operating results and cash flows for interim periods are not necessarily indicative of results that can be expected for the entire year. The information included in this report should be read in conjunction with our audited consolidated financial statements and notes thereto included in our Annual Report on Form 10 -K for the year ended March 31, 2016. The summary of our significant accounting policies is incorporated by reference to our Annual Report on Form 10 -K for the year ended March 31, 2016.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Issued Accounting Pronouncements In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2016 - 09, Compensation—Stock Compensation (Topic 718) , as part of its simplification initiative, which affects all entities that issue share-based payment awards to their employees. The amendments in this update cover such areas as the recognition of excess tax benefits and deficiencies, the classification of those excess tax benefits on the statement of cash flows, an accounting policy election for forfeitures, the amount an employer can withhold to cover income taxes and still qualify for equity classification and the classification of those taxes paid on the statement of cash flows. The ASU was effective for our fiscal year ending March 31, 2018 using either the prospective, retrospective or modified retrospective transition method, depending on the area covered in this update. As permitted within the amendment, we elected to early adopt and prospectively apply the provisions of this amendment as of April 1, 2015. As a result of the adoption of ASU No. 2016 - 09, the captions of income taxes, net income, and net income per share basic and diluted on the condensed consolidated statements of income for the three months ended December 31, 2015 have been restated to $854,000, $2,597,000, $0.72 and $0.69 as compared to amounts previously reported of $1,090,000, $2,361,000, $0.65 and $0.63, respectively. The captions of net income and total comprehensive income on the condensed consolidated statements of comprehensive income for the three months ended December 31, 2015 have been restated to $2,597,000 and $750,000 as compared to amounts previously reported of $2,361,000 and $514,000, respectively. As a result of the adoption of ASU No. 2016 - 09, the captions of income taxes, net income, and net income per share basic and diluted on the condensed consolidated statements of income for the nine months ended December 31, 2015 have been restated to $2,592,000, $7,178,000, $2.00 and $1.91 as compared to amounts previously reported of $3,351,000, $6,419,000, $1.79 and $1.72, respectively. The captions of net income and total comprehensive income on the condensed consolidated statements of comprehensive income for the nine months ended December 31, 2015 have been restated to $7,178,000 and $5,962,000 as compared to amounts previously reported of $6,419,000 and $5,203,000, respectively. The captions of net income and accrued liabilities and taxes payable on the condensed consolidated statements of cash flows for the nine months ended December 31, 2015 have been restated to $7,178,000 and ($49,000) as compared to amounts previously reported of $6,419,000 and $710,000, respectively. In December 2015, the FASB issued ASU No. 2015 - 17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes (“ ASU 2015 - 17” ). ASU 2015 - 17 simplifies the presentation of deferred income taxes by requiring that deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. The standard was effective for our fiscal year (and interim periods within that year) ending March 31, 2018. As permitted within the amendment, we elected to early adopt and prospectively apply the provisions of this amendment as of April 1, 2016. In May 2014, the FASB issued ASU No. 2014 - 09, Revenue from Contracts with Customers (Topic 606) , which impacts virtually all aspects of an entity’ s revenue recognition. The core principle of the new standard is that revenue should be recognized to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. Companies can transition to the standard either retrospectively or as a cumulative effective adjustment as of the date of adoption. The new standard is effective for our fiscal year (and interim periods within that year) ending March 31, 2019. We are currently evaluating when to adopt the new standard, the impacts of adoption and the implementation approach to be used.