Note 15 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Notes Tables

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

	Year Ended December 31,
	2018		2017		2016
	(Dollars in thousands, except per share data)
Cost of revenues	$	3,488	$	3,369	$	2,400
Selling and marketing expenses		792		452		247
General and administrative expenses		5,938		4,939		2,510
Total stock-based compensation expense		10,218		8,760		5,157
Tax effect on stock-based compensation expense		668		604		617
Net effect of stock-based compensation expense	$	9,550	$	8,156	$	4,540

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	Year Ended December 31,
	2018			2017			2016
For stock options issued by the Company:
Risk-free interest rates		2.8	%		1.9	%		1.3	%
Expected lives (in weighted average years)		3.5			3.1			4.5
Dividend yield		0.90	%		0.62	%		1.10	%
Expected volatility (weighted average)		25.5	%		27.2	%		30.7	%
Forfeiture rate (weighted average)		3.1	%		0.0	%		8.4	%

Schedule of Share-based Payment Award, Equity Awards Other than Options, Valuation Assumptions [Table Text Block]

Risk-free interest rate	1.29	%
Expected life (in years)	6
Dividend yield	1.14	%
Expected volatility	30.7	%
Forfeiture rate:
Senior management	0.0	%
Other employees	10.5	%
Sub-Optimal Exercise Factor:
Senior management	2.5
Other employees	2.0

Risk-free interest rate	1.65	%
Expected life (in years)	7
Dividend yield	1.1	%
Expected volatility	30.6	%
Forfeiture rate	0.0	%
Sub-Optimal Exercise Factor	2.5

Risk-free interest rate	1.74	%
Expected life (in years)	5
Dividend yield	0.66	%
Expected volatility	26.3	%
Forfeiture rate	10.3	%
Sub-Optimal Exercise Factor	2

Risk-free interest rate	2.08	%
Expected life (in years)	7
Dividend yield	0.69	%
Expected volatility	29.4	%
Forfeiture rate	0.0	%
Sub-Optimal Exercise Factor	2.5

Risk-free interest rate	2.1	%
Expected life (in years)	6
Dividend yield	0.6	%
Expected volatility	26.9	%
Forfeiture rate	0.0	%
Sub-Optimal Exercise Factor	2.5

Risk-free interest rate	2.84	%
Expected life (in years)	1.9 – 3.5
Dividend yield	0.79	%
Expected volatility	25.24	%
Forfeiture rate	0.0	%
Sub-Optimal Exercise Factor	2.5

Risk-free interest rate	2.79	%
Expected life (in years)	3.5 – 3.7
Dividend yield	0.92	%
Expected volatility	25.64	%
Forfeiture rate for employees	2.78	%
Forfeiture rate for members of the senior management	0.0	%
Sub-Optimal Exercise Factor for employees	2.0
Sub-Optimal Exercise Factor for members of the senior management	2.8

Risk-free interest rate	3.11	%
Expected life (in years)	2.0 – 3.6
Dividend yield	1.03	%
Expected volatility	25.87	%
Forfeiture rate for directors	0.0	%
Forfeiture rate for employees	2.78	%
Sub-Optimal Exercise Factor for directors	2.8
Sub-Optimal Exercise Factor for employees	2.0

Schedule of Share-based Compensation, Stock Options and Stock Appreciation Rights Award Activity [Table Text Block]

	Year Ended December 31,
	2018					2017					2016
	Shares (In thousands)			Weighted Average Exercise Price		Shares (In thousands)			Weighted Average Exercise Price		Shares (In thousands)			Weighted Average Exercise Price
Outstanding at beginning of year		1,548		$	41.35		2,565		$	33.36		2,438		$	25.38
Granted, at fair value:
Stock Options		—			—		30			57.97		1,155			43.01
SARs*		1,172			53.87		132			62.55		—			—
RSUs**		74			—		23			—		—			—
Exercised		(203	)		29.75		(1,181	)		25.92		(967	)		25.33
Forfeited		(64	)		45.73		(21	)		46.15		(57	)		24.12
Expired		—			—		—			—		(4	)		26.84
Outstanding at end of year		2,527			46.77		1,548			41.35		2,565			33.36
Options and SARs exercisable at end of year		846			42.06		431			32.61		557			25.22
Weighted-average fair value of options and SARs granted during the year				$	16.45				$	22.82				$	11.61

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]

		Options Outstanding						Options Exercisable
Exercise Price		Number of Stock-based Awards Outstanding		Weighted Average Remaining Contractual Life in Years		Aggregate Intrinsic Value		Number of Stock-based Awards Exercisable		Weighted Average Remaining Contractual Life in Years		Aggregate Intrinsic Value
$	-		75		1.8		3,933		-		-		-
	20.13		29		0.3		924		29		0.3		924
	23.34		99		0.4		2,897		99		0.4		2,897
	35.15		15		4.1		257		15		4.1		257
	38.24		15		3.8		211		15		3.8		211
	42.87		942		3.5		8,879		521		3.5		4,918
	47.46		38		4.9		182		38		4.9		182
	53.16		35		5.9		-		-		-		-
	53.44		828		5.5		-		-		-		-
	55.16		296		4.9		-		66		4.9		-
	57.97		30		5.6		-		30		5.6		-
	58.79		16		3.5		-		-		-		-
	63.35		109		4.9		-		33		4.9		-
			2,527		4.3	$	17,283		846		3.3	$	9,389

		Options Outstanding						Options Exercisable
Exercise Price		Number of Stock-based Awards Outstanding		Weighted Average Remaining Contractual Life in Years		Aggregate Intrinsic Value		Number of Stock-based Awards Exercisable		Weighted Average Remaining Contractual Life in Years		Aggregate Intrinsic Value
$	-		23		3.9		1,455		-		-		-
	20.13		35		1.3		1,533		35		1.3		1,533
	23.34		176		1.4		7,150		176		1.4		7,150
	25.65		10		0.3		398		10		0.3		398
	35.15		15		5.1		432		15		5.1		432
	38.24		15		4.8		386		15		4.8		386
	42.87		1,074		4.5		22,651		143		4.5		3,005
	47.46		38		5.9		619		38		5.9		619
	57.97		30		6.6		180		-		-		-
	58.79		23		4.5		120		-		-		-
	63.35		109		5.9		66		-		-		-
			1,548		4.2	$	34,990		432		3.0	$	13,523