Note 6 - Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2017

Notes Tables

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

	Three Months Ended March 31,
	2017			2016
Stock-based compensation expense, gross	$	1,337		$	1,284
Income tax benefit at our statutory rate associated with stock-based compensation		(521	)		(501	)
Stock-based compensation expense, net	$	816		$	783

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

	Three Months Ended
	March 31, 2017					March 31, 2016
				Weighted-					Weighted-
				Average					Average
	Number			Grant Date		Number			Grant Date
	of			Fair Value		of			Fair Value
	Shares			Per Share		Shares			Per Share
Restricted common stock:
Outstanding - beginning of period		396,033		$	12.06		337,506		$	9.57
Granted		307,943		$	10.40		237,500		$	12.88
Vested		(200,291	)	$	11.82		(178,973	)	$	8.46
Outstanding - end of period		503,685		$	11.14		396,033		$	12.06
Restricted Class A common stock:
Outstanding - beginning of period		415,082		$	10.15		374,693		$	9.46
Granted		198,220		$	10.60		218,612		$	11.25
Vested		(227,526	)	$	10.00		(178,223	)	$	10.04
Outstanding - end of period		385,776		$	10.47		415,082		$	10.15