Note 16 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Stockholders' Equity Attributable to Parent	$ 1,897,766		$ 1,897,766		$ 1,828,539
Stockholders' Equity, Period Increase (Decrease)			69,200
Net Income (Loss) Attributable to Parent	$ 51,415	$ 34,831	100,356	$ 80,994
Dividends, Common Stock, Cash			33,500
Adjustments Related to Tax Withholding for Share-based Compensation			$ 5,100
U.S. Treasury [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights					$ 20.65	$ 20.96
Class of Warrant or Right, Increase in Warrants Exercisable, Percentage					1.50%
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	943,345		943,345		943,345	1,846,374