Note 10 - Stock Based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock Options Activity

The following table is a summary of the Company’s stock options:  

Options	Number of Shares			Weighted Average Exercise Price
Outstanding at December 31, 2017		1,484,914		$	32.53
Exercised		(112,669	)		24.16
Forfeited or expired		(5,311	)		36.94
Outstanding at March 31, 2018		1,366,934			33.20
Granted		14,265			53.70
Exercised		(93,500	)		20.07
Forfeited or expired		(6,759	)		35.06
Outstanding at June 30, 2018		1,280,940			34.38
Exercisable at June 30, 2018		544,596		$	26.37

Summary of Unvested Stock Options, Restricted Stock and Performance Shares

The following table is a summary of the Company’s unvested stock options, restricted stock and performance shares for which the requisite service period has not been rendered but that are expected to vest on the achievement of a performance condition:

	Unvested Stock Options					Unvested Restricted Stock					Unvested Performance Shares
	Number of Shares			Weighted- Average Grant-Date Fair Value		Number of Shares			Weighted- Average Grant-Date Fair Value		Number of Shares			Weighted- Average Grant-Date Fair Value
Unvested at December 31, 2017		757,269		$	15.20		265		$	44.23		276,250		$	42.08
Vested during period		(21,510	)		13.99		-			-		-			-
Forfeited		(5,311	)		13.90		-			-		(17,250	)		40.65
Unvested at March 31, 2018		730,448			15.25		265			44.23		259,000			42.17
Granted		14,265			24.54		9,779			53.70		17,250			40.65
Vested during period		(1,610	)		17.34		(265	)		44.23		-			-
Forfeited		(6,759	)		13.27		-			-		(28,750	)		41.36
Unvested at June 30, 2018		736,344		$	15.44		9,779		$	53.70		247,500		$	42.16