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Note 16 - Share-Based and Other Compensation Programs Non-Qualified Stock Options (Details) - Non-Qualified Stock Options
$ / shares in Units, $ in Thousands

12 Months Ended

Dec. 31, 2018

USD ($)

$ / shares

shares

Dec. 31, 2017

USD ($)

$ / shares

shares

Dec. 31, 2016

USD ($)

days

$ / shares

shares

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Outstanding, Beginning of Period, Number of Shares | shares

1,692,743

2,839,738

Outstanding, Beginning of Period, Weighted Average Exercise Price Per Share

$ 8.16

Exercised, Number of Shares | shares

(375,573)

Exercised, Weighted Average Exercise Price Per Share

$ 3.79

Forfeited, Number of Shares | shares

(4,379)

Forfeited, Weighted Average Exercise Price Per Share

$ 14.38

Expired, Number of Shares | shares

0

Expired, Weighted Average Exercise Price Per Share

$ 0

Outstanding, End of Period, Number of Shares | shares

1,312,791

1,692,743

2,839,738

Outstanding, End of Period, Weighted Average Exercise Price Per Share

$ 9.39

$ 8.16

Options Outstanding, Weighted Average Remaining Contractual Life (Years)

4 years 10 months 24 days

Total intrinsic value of options outstanding | $

^[1]

$ 9,500

Exercisable, Number of Shares | shares

966,478

Exercisable, Weighted Average Exercise Price Per Share

$ 7.91

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable, Weighted Average Remaining Contractual Term

4 years

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value | $

^[1]

$ 8,361

Available for grant | shares

7,906,190

Share Price

$ 16.36

Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value | $

$ 6,274

$ 14,389

$ 1,519

Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options (Deprecated 2017-01-31) | $

1,318

5,036

532

Proceeds from Stock Options Exercised | $

1,425

7,131

717

Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value | $

$ 1,300

$ 3,300

$ 1,300

Number of Consecutive Trading Days For Current Year Options Granted Vesting Requirement | days

10

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term

4 years

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate

^[2]

1.72%

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate

^[3]

94.20%

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate

0.08%

Minimum

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term

3 years 9 days

Maximum

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term

4 years

Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period

4 years

2018 Award Year

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Granted, Number of Shares | shares

0

Granted, Weighted Average Exercise Price Per Share

$ 0

Weighted average fair value per share of stock options granted

^[4]

$ 0

2017 Award Year

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Granted, Number of Shares | shares

0

Weighted average fair value per share of stock options granted

^[4]

$ 0

2016 Award Year

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Granted, Number of Shares | shares

342,090

Weighted average fair value per share of stock options granted

^[4]

$ 9.72

Share-based Compensation Arrangement by Share-based Payment Award, Shares Granted in Period, Percent of Increase Over Granted Price for Additional Vesting Criteria

125.00%

2016 Award Year | Minimum

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Share-based Compensation Arrangement by Share-based Payment Award, Shares Granted in Period, Closing Price of Common Stock Vesting Criteria

$ 15.20

Share-based Compensation Award, Tranche One

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

50.00%

Share-based Compensation Award, Tranche Two

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage

50.00%

[1]

Based on the market price of $16.36 at December 31, 2018.

[2]

The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant.

[3]

Volatility is determined at the date of grant using historical share price volatility and expected life of each award.

[4]

We use the Monte Carlo valuation model in determining the grant date fair value of stock options issued to executives and non-executives using the assumptions noted in the following table:

	Year Ended December 31,
	2016
Derived service period (years)	3.02 - 4.00
Risk-free interest rate (a)	1.72	%
Volatility (b)	94.20	%
Dividend yield	0.08	%

______________________

(a) The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant.

(b)

Volatility is determined at the date of grant using historical share price volatility and expected life of each award.

X

- Definition

Number of Consecutive Trading Days For Vesting Requirement of Current Year Share-based Payment Awards

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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