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

12 Months Ended

Dec. 31, 2017

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, 2017		3,489,826		$	21.42
Granted		472,463			33.89
Exercised		(1,205,281	)		18.56
Forfeited		(32,700	)		27.05
Balance of Outstanding Options at December 31, 2017		2,724,308		$	24.78		6.43	$	70,910,167
Expected to vest a fter December 31, 2017		1,784,417		$	26.74		7.68	$	42,945,946
Vested and exercisable at December 31, 2017		888,246		$	20.75		3.85	$	26,701,699

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, 2017		1,881,578		$	11.28
Granted		472,463			12.33
Vested		(485,279	)		12.92
Forfeited		(32,700	)		11.07
Non-vested at December 31, 201 7		1,836,062		$	11.12

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, 2017		519,173						$	21.21
Granted		274,390							31.37
Vested		(253,431	)						22.64
Forfeited		−							−
Outstanding non-vested at December 31, 2017		540,132			8.5	$	26,043,230	$	25.71
Expected to vest after December 31, 201 7		538,462			8.5	$	25,962,706