Note 3 - Share-based Compensation Plans - Stock Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018		Dec. 31, 2017
Unvested units (in shares)	1,060,525	1,574,032
Unvested, weighted average grant date fair value (in dollars per share)	$ 12.09	$ 11.29
Unvested, value	$ 10,571	$ 10,760		$ 17,804
Granted units (in shares)	499,626	249,751	[1]
Grant price (in dollars per share)	$ 10.16	$ 11.54	[1]
Granted, value	$ 5,074	$ 2,882	[1]
Vested units (in shares)	(530,446)	(742,607)	[1]
Vested, weighted average grant date fair value (in dollars per share)	$ 10.18	$ 10.20	[1]
Vested, value	$ (5,138)	$ (9,681)	[1]
Forfeited units (in shares)	(9,032)	(20,651)
Forfeited, weighted average grant date fair value (in dollars per share)	$ 13.84	$ 11.90
Forfeited, value	$ (125)	$ (245)
Unvested units (in shares)	1,020,673	1,060,525
Unvested, weighted average grant date fair value (in dollars per share)	$ 12.12	$ 12.09
Restricted Stock Units (RSUs) [Member]
Unvested units (in shares)	661,137	1,171,353
Unvested, weighted average grant date fair value (in dollars per share)	$ 10.16	$ 9.91
Unvested, value	$ 2,328	$ 4,653		11,647
Granted units (in shares)	294,871	249,751	[1]
Grant price (in dollars per share)	$ 9.96	$ 11.54	[1]
Granted, value	$ 2,938	$ 2,882	[1]
Vested units (in shares)	(530,446)	(742,607)	[1]
Vested, weighted average grant date fair value (in dollars per share)	$ 10.18	$ 10.20	[1]
Vested, value	$ (5,138)	$ (9,681)	[1]
Forfeited units (in shares)	(9,032)	(17,360)
Forfeited, weighted average grant date fair value (in dollars per share)	$ 13.84	$ 11.25
Forfeited, value	$ (125)	$ (195)
Unvested units (in shares)	416,530	661,137
Unvested, weighted average grant date fair value (in dollars per share)	$ 9.92	$ 10.16
Performance Stock Units (PSUs) [Member]
Unvested units (in shares)	399,388	402,679
Unvested, weighted average grant date fair value (in dollars per share)	$ 15.29	$ 15.29
Unvested, value	$ 8,243	$ 6,107		$ 6,157
Granted units (in shares)	204,755		[1]
Grant price (in dollars per share)	$ 10.43		[1]
Granted, value	$ 2,136		[1]
Vested units (in shares)			[1]
Vested, weighted average grant date fair value (in dollars per share)			[1]
Vested, value			[1]
Forfeited units (in shares)		(3,291)
Forfeited, weighted average grant date fair value (in dollars per share)		$ 15.29
Forfeited, value		$ (50)
Unvested units (in shares)	604,143	399,388
Unvested, weighted average grant date fair value (in dollars per share)	$ 13.64	$ 15.29

[1] Includes 201,969 shares of common stock issued in settlement for 2017 performance bonuses, which were paid in 2018.