Note 11 - Share Based Compensation and Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

Share-based Compensation, Stock Options, Activity [Table Text Block]

						Weighted
				Weighted		Average
				Average		Remaining		Aggregate
				Exercise		Contractual		Intrinsic
Options	Shares			Price		Life (in Years)		Value
Balance of Outstanding Options at January 1, 2018		2,724,308		$	24.78
Granted		459,663			42.99
Exercised		(126,027	)		21.77
Forfeited		(73,664	)		28.21
Balance of Outstanding Options at December 31, 2018		2,984,280		$	27.63		6.04	$	24,290,404
Expected to vest after December 31, 2018		1,750,298		$	30.62		7.63	$	10,524,034
Vested and exercisable at December 31, 2018		1,187,924		$	23.15		3.64	$	13,457,583

Schedule of Nonvested Share Activity [Table Text Block]

				Weighted
				Average
	Number of			Grant Date
Non-vested Shares	Shares			Fair Value
Non-vested at January 1, 2018		1,836,062		$	11.12
Granted		459,663			15.46
Vested		(430,040	)		13.26
Forfeited		(69,329	)		10.73
Non-vested at December 31, 2018		1,796,356		$	11.74

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity [Table Text Block]

				Weighted
				Average				Weighted
				Remaining		Aggregate		Average
				Contractual		Intrinsic		Grant Date
Stock Awards and Units	Shares			Life (in Years)		Value		Fair Value
Outstanding non-vested shares at January 1, 2018		540,132						$	25.71
Granted		306,590							40.46
Vested		(267,588	)						24.57
Forfeited		(6,000	)						33.62
Outstanding non-vested at December 31, 2018		573,134			8.6	$	20,402,823	$	34.07
Expected to vest after December 31, 2018		571,974			8.6	$	20,361,531