Note 13 - Stockholders' Equity - Stock Options, SARs and RSUs Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Options outstanding at beginning of year (in shares)		1,831	[1],[2],[3]	1,992	[1],[2],[3]	2,152
Options outstanding at beginning of year, weighted average exercise price (in dollars per share)		$ 4.59	[1],[2],[3]	$ 5.02	[1],[2],[3]	$ 5.12
Options outstanding at beginning of year	[1]
Options granted (in shares)		10		54		78
Options granted, weighted average exercise price (in dollars per share)		$ 12.61		$ 12.42		$ 11.93
Options granted, aggregate intrinsic value	[1]
Exercised (in shares)	[1]	(663)		(723)		(818)
Exercised, weighted average exercise price (in dollars per share)	[1]	$ 2.59		$ 2.81		$ 3.77
Exercised, aggregate intrinsic value	[1]	$ 7,519		$ 6,845		$ 6,699
Forfeited and cancelled (in shares)		(99)		(68)		(86)
Forfeited and cancelled, weighted average exercise price (in dollars per share)		$ 1.59		$ 5.63		$ 9.85
Forfeited and cancelled, aggregate intrinsic value	[1]
Options outstanding at end of year (in shares)	[1],[2],[3]	1,735		1,831		1,992
Options outstanding at end of year, weighted average exercise price (in dollars per share)	[1],[2],[3]	$ 3.84		$ 4.59		$ 5.02
Options/SARs/RSUs outstanding at end of year (1,2,4)	[1],[2],[3]	$ 20,639		$ 12,281		$ 14,931
Options/SARs exercisable at end of year (1,3,4) (in shares)	[1],[3],[4]	604		704		813
Options/SARs exercisable at end of year (1,3,4) (in dollars per share)	[1],[3],[4]	$ 9.75		$ 9.10		$ 8.20
Options/SARs exercisable at end of year (1,3,4)	[1],[3],[4]	$ 3,619		$ 1,576		$ 3,499
Stock Appreciation Rights (SARs) [Member]
Non-option instruments granted (in shares)				13		190
Non-option instruments, weighted average exercise price (in dollars per share)				$ 12.50		$ 10.40
Non-option instruments, aggregate intrinsic value	[1]
Restricted Stock Units (RSUs) [Member]
Non-option instruments granted (in shares)		656		563		476
Non-option instruments, weighted average exercise price (in dollars per share)
Non-option instruments, aggregate intrinsic value	[1]

[1] Calculation of aggregate intrinsic value for options, RSUs and SARs outstanding and exercisable is based on the share price of the Company's common stock as of December 31, 2019, 2018 and 2017 which was $15.74, $11.20 and $12.50 per share, respectively. The intrinsic value for options and SARs exercised and RSUs vested during those years represents the difference between the fair market value of the Company's common stock on the date of exercise and vesting for RSUs and the exercise price of each option, RSU or SAR, as applicable.

[2] Due to the ceiling imposed on the SAR grants, the outstanding amount above can be exercised for a maximum of 1,665 thousand shares of the Company's common stock as of December 31, 2019.

[3] SAR grants made on or after January 1, 2012 are convertible for a maximum number of shares of the Company's common stock equal to 50% of the SAR units subject to the grant.

[4] Due to the ceiling imposed on the SAR grants, the exercisable amount above can be exercised for a maximum of 561 thousand shares of the Company's common stock as of December 31, 2019.