Condensed Consolidated Balance Sheets (Current Period Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Common Class A [Member]
Par value (in dollars per share)	$ 0.01	$ 0.01
Shares authorized (in shares)	20,000,000	20,000,000
Shares issued (in shares)	15,922,879	15,844,319
Shares outstanding (in shares)	15,844,319	15,773,381
Common Class B [Member]
Par value (in dollars per share)	$ 0.01	$ 0.01
Shares authorized (in shares)	5,000,000	5,000,000
Shares issued (in shares)	2,350,000	2,350,000
Shares outstanding (in shares)	2,350,000	2,350,000
Accounts receivable allowance	$ 1,288	$ 1,857
Drivers' advances and other receivables, allowance	$ 1,100	$ 1,005
Treasury stock, shares (in shares)	78,560	149,498