Note 11 - Equity-based Compensation - Summary of Stock Award Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock Awards, Outstanding (in shares)	1,143,205	1,428,878	1,501,021
Weighted average award date fair value (in dollars per share)	$ 23.26	$ 21.53	$ 20.58
Stock Awards, Outstanding (in shares)	1,034,964	1,143,205	1,428,878
Weighted average award date fair value (in dollars per share)	$ 23.20	$ 23.26	$ 21.53
Restricted Stock Units (RSUs) [Member]
Awards, grants during period (in shares)	325,321	281,567	257,532
Weighted average award date fair value, award granted (in dollars per share)	$ 20.02	$ 24.13	$ 23.06
Awards, distributed during period (in shares)	(237,416)	(312,182)	(95,510)
Weighted average award date fair value, award distributed (in dollars per share)	$ 18.83	$ 17.47	$ 20.71
Awards, forfeited during period (in shares)	(74,075)	(90,896)	(81,626)
Weighted average award date fair value, award forfeited (in dollars per share)	$ 22.09	$ 21.79	$ 20.36
Performance Shares [Member]
Awards, grants during period (in shares)	146,367	219,943	213,436
Weighted average award date fair value, award granted (in dollars per share)	$ 22.78	$ 23.25	$ 28.18
Awards, distributed during period (in shares)	(111,155)	(296,909)	(49,672)
Weighted average award date fair value, award distributed (in dollars per share)	$ 25.85	$ 21.55	$ 21.95
Awards, forfeited during period (in shares)	(80,597)	(87,196)	(136,050)
Weighted average award date fair value, award forfeited (in dollars per share)	$ 25.30	$ 25.95	$ 24.29
Restricted Stock [Member]
Awards, distributed during period (in shares)	(76,686)	0	(179,169)
Weighted average award date fair value, award distributed (in dollars per share)	$ 18.26	$ 0	$ 22.44
Awards, forfeited during period (in shares)	0	0	(1,084)
Weighted average award date fair value, award forfeited (in dollars per share)	$ 0	$ 0	$ 23.01