Note 15 - Accelerated Share Repurchases (Details Textual) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands								8 Months Ended	12 Months Ended
	Jan. 17, 2020	Jan. 17, 2020	May 08, 2019	May 07, 2019	Jul. 19, 2018	Jul. 19, 2018	May 24, 2018	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 14, 2020	May 02, 2019	Jul. 16, 2018
Stock Repurchase Program, Authorized Amount													$ 50,000
Payments for Repurchase of Common Stock									$ 30,000	$ 30,000
Common Stock [Member]
Stock Repurchased During Period, Shares									452	806
Accelerated Stock Repurchase [Member]
Stock Repurchase Program, Authorized Amount				$ 30,000									30,000
Payments for Repurchase of Common Stock				$ 30,000
Stock Repurchased During Period, Shares			500
Share Price			$ 39.85
Share Repurchased, Pecentage			60.00%
Accelerated Stock Repurchase [Member] | Morgan Stanley & Co., LLC [Member]
Payments for Repurchase of Common Stock							$ 30,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount														$ 12,000
Number of Additional Shares Deliver to Company if ASR Agreement Settled					400
Stock Repurchased and Retired During Period, Shares						800	400
Accelerated Share Repurchases, Final Price Paid Per Share						$ 37.18
Accelerated Stock Repurchase [Member] | Morgan Stanley & Co., LLC [Member] | Common Stock [Member]
Stock Repurchase Program, Authorized Amount							$ 30,000
Accelerated Share Repurchases, Initial Price Paid Per Share							$ 41.41
Accelerated Stock Repurchase [Member] | Subsequent Event [Member]
Stock Repurchase Program, Remaining Authorized Repurchase Amount												$ 12,000
Accelerated Stock Repurchase [Member] | Subsequent Event [Member] | Morgan Stanley & Co., LLC [Member]
Number of Additional Shares Deliver to Company if ASR Agreement Settled		100
Stock Repurchased and Retired During Period, Shares	600
Accelerated Share Repurchases, Final Price Paid Per Share	$ 50.78
Repurchase from Open Market [Member]
Stock Repurchase Program, Authorized Amount													$ 20,000
Treasury Stock, Shares, Acquired								0