Note 16 - Stockholders' Equity (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Stockholders' Equity Attributable to Parent	$ 1,760,000		$ 1,760,000		$ 1,750,000
Stockholders' Equity, Period Increase (Decrease)	11,300
Net Income (Loss) Attributable to Parent	34,831	$ 45,200	80,994	$ 81,180	81,000
Other Comprehensive Income (Loss), Net of Tax	2,215	$ (2,136)	$ 9,568	$ 2,787	$ 9,600
Treasury Stock, Value, Acquired, Cost Method	54,400
Dividends, Common Stock, Cash	$ 28,400