Note 7 - Summary of Restricted Common Stock Activity (Details) - Restricted Stock [Member] - $ / shares	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Common Class A [Member]
Outstanding - beginning of period (in shares)	204,473
Outstanding - beginning of period (in dollars per share)	$ 9.81
Granted (in shares)	287,513	236,294
Granted (in dollars per share)	$ 9.37	$ 9.80
Vested (in shares)	(117,293)	(31,821)
Vested (in dollars per share)	$ 9.85	$ 9.75
Outstanding - end of period (in shares)	374,693	204,473
Outstanding - end of period (in dollars per share)	$ 9.46	$ 9.81
Outstanding - beginning of period (in shares)	385,056	274,838
Outstanding - beginning of period (in dollars per share)	$ 9.09	$ 4.43
Granted (in shares)	150,308	312,961
Granted (in dollars per share)	$ 10.27	$ 11.78
Vested (in shares)	(197,858)	(202,743)
Vested (in dollars per share)	$ 9.16	$ 6.93
Outstanding - end of period (in shares)	337,506	385,056
Outstanding - end of period (in dollars per share)	$ 9.57	$ 9.09