Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Allowance for doubtful accounts	$ 203	$ 201
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	2,000,000us-gaap_PreferredStockSharesAuthorized	2,000,000us-gaap_PreferredStockSharesAuthorized
Preferred stock, shares issued (in shares)	0us-gaap_PreferredStockSharesIssued	0us-gaap_PreferredStockSharesIssued
Common Class A [Member]
Common Stock, Par Value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, Shares Authorized (in shares)	60,000,000	60,000,000
Common Stock, Shares Issued (in shares)	25,538,056	25,475,662
Common Stock, Shares Outstanding (in shares)	20,939,430	20,894,286
Treasury stock, Shares (in shares)	4,598,626	4,581,376
Common Class B [Member]
Common Stock, Par Value (in dollars per share)	$ 0.001	$ 0.001
Common Stock, Shares Authorized (in shares)	80,000,000	80,000,000
Common Stock, Shares Issued (in shares)	4,262,287	4,251,889
Common Stock, Shares Outstanding (in shares)	3,502,644	3,494,865
Treasury stock, Shares (in shares)	759,643	757,024

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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