Note 15 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block]

	Year Ended December 31,
	2019		2018		2017
	(Dollars in thousands)
Cost of revenues	$	3,633	$	3,488	$	3,369
Selling and marketing expenses		4,810		792		452
General and administrative expenses		916		5,938		4,939
Total stock-based compensation expense		9,359		10,218		8,760
Tax effect on stock-based compensation expense		736		668		604
Net effect of stock-based compensation expense	$	8,623	$	9,550	$	8,156

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

	Year Ended December 31,
	2019			2018			2017
For stock based awards issued by the Company:
Risk-free interest rates		1.8	%		2.8	%		1.9	%
Expected lives (in weighted average years)		3.5			3.5			3.1
Dividend yield		0.7	%		0.9	%		0.62	%
Expected volatility (weighted average)		25.1	%		25.5	%		27.2	%

	Year Ended December 31,
	2019			2018			2017
Weighted average forfeiture rate		8.6	%		3.1	%		—	%

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

Risk-free interest rate	1.79	%
Expected life (in years)	3.5
Dividend yield	0.57	%
Expected volatility	24.80	%
Forfeiture rate for directors	0.0	%
Sub-Optimal Exercise Factor for directors	2.8

Share-based Payment Arrangement, Option and Stock Appreciation Rights, Activity [Table Text Block]

	Year Ended December 31,
	2019					2018					2017
	Awards (In thousands)			Weighted Average Exercise Price		Awards (In thousands)			Weighted Average Exercise Price		Awards (In thousands)			Weighted Average Exercise Price
Outstanding at beginning of year		2,527		$	46.77		1,548		$	41.35		2,565		$	33.36
Granted, at fair value:
Stock Options		—			—		—			—		30			57.97
SARs*		38			69.13		1,172			53.87		132			62.55
RSUs**		9			—		74			—		23			—
Exercised		(711	)		37.83		(203	)		29.75		(1,181	)		25.92
Forfeited		(71	)		50.59		(64	)		45.73		(21	)		46.15
Expired		—			—		—			—		—			—
Outstanding at end of year		1,792			50.39		2,527			46.77		1,548			41.35
Options and SARs exercisable at end of year		479			48.35		846			42.06		431			32.61
Weighted-average fair value of options and SARs granted during the year				$	29.24				$	16.45				$	22.82

Share-based Payment Arrangement, Option, Exercise Price Range [Table Text Block]

		Awards Outstanding						Awards 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
$	—		59		1.5	$	4,369		—		—	$	—
	42.87		427		2.5		13,517		230		2.5		7,295
	47.46		15		3.9		406		15		3.9		406
	51.71		8		5.0		182		—		—		—
	53.16		35		4.9		756		15		4.9		329
	53.44		783		4.5		16,498		—		—		—
	55.16		296		3.9		5,724		131		3.9		2,527
	57.97		30		4.6		497		30		4.6		497
	58.79		12		2.5		187		6		2.5		94
	63.35		98		3.9		1,094		52		3.9		581
	71.71		4		5.6		11		—		—		—
	72.14		15		5.7		36		—		—		—
	76.43		10		5.9		—		—		—		—
			1,792		3.8	$	43,277		479		3.2	$	11,729

		Awards Outstanding						Awards 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