Note 8 - Earnings Per Share (Details Textual)	3 Months Ended	9 Months Ended
Sep. 30, 2016 shares	Sep. 30, 2015 shares	Sep. 30, 2016 shares	Sep. 30, 2015 shares
Common Class A [Member] \| Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	508,230	736,350	710,420	535,474
Common Class A [Member]
Common Stock to Dividend or Distribution Payable			0.167
Common Class B [Member] \| Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	118,830	66,227	104,157	55,801

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Antidilution
-URI http://asc.fasb.org/extlink&oid=6505113

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Diluted Earnings Per Share
-URI http://asc.fasb.org/extlink&oid=6510752

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Contingent Stock Agreement
-URI http://asc.fasb.org/extlink&oid=6508534

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration