Note 6 - Stock-based Compensation (Tables)

9 Months Ended

Sep. 30, 2016

Notes Tables

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

	Three Months Ended						Nine Months Ended
	September 30,						September 30,
	2016			2015			2016			2015
Stock-based compensation expense, gross	$	1,271		$	1,009		$	3,827		$	3,011
Income tax benefit at our statutory rate associated with share-based compensation		(496	)		(394	)		(1,493	)		(1,174	)
Stock-based compensation expense, net	$	775		$	615		$	2,334		$	1,837

Schedule of Nonvested Restricted Stock Units Activity [Table Text Block]

	Nine Months Ended
	September 30, 2016					September 30, 2015
				Weighted-					Weighted-
				average					average
				Grant Date					Grant Date
	Number of			Fair Value		Number of			Fair Value
	Shares			Per Share		Shares			Per Share
Restricted stock - common:
Outstanding - beginning of period		337,506		$	9.57		385,056		$	9.09
Granted		237,500		$	12.88		150,308		$	10.27
Vested		(178,973	)	$	8.46		(197,858	)	$	9.16
Outstanding - end of period		396,033		$	12.06		337,506		$	9.57

	Nine Months Ended
	September 30, 2016					September 30, 2015
				Weighted-average					Weighted-average
				Grant Date					Grant Date
	Number of			Fair Value		Number of			Fair Value
	Shares			Per Share		Shares			Per Share
Restricted stock - class A common:
Outstanding - beginning of period		374,693		$	9.46		204,473		$	9.81
Granted		218,612		$	11.25		287,513		$	9.37
Vested		(178,223	)	$	10.04		(117,293	)	$	9.85
Outstanding - end of period		415,082		$	10.15		374,693		$	9.46