Note 9 - Non-vested Stock (Details)	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Common Class A [Member]
Outstanding (in shares) | shares	110,646
Outstanding (in dollars per share) | $ / shares	$ 11.10
Granted (in shares) | shares	89,416
Granted (in dollars per share) | $ / shares	$ 13.51
Forfeited (in shares) | shares	(16,248)
Forfeited (in dollars per share) | $ / shares	$ 5.39
Outstanding (in shares) | shares	183,814
Outstanding (in dollars per share) | $ / shares	$ 12.78
Common Class B [Member]
Outstanding (in shares) | shares	18,441
Outstanding (in dollars per share) | $ / shares	$ 36.42
Granted (in shares) | shares	14,902
Granted (in dollars per share) | $ / shares	$ 36.72
Forfeited (in shares) | shares	(2,708)
Forfeited (in dollars per share) | $ / shares	$ 32.31
Outstanding (in shares) | shares	30,635
Outstanding (in dollars per share) | $ / shares	$ 36.93