Note 10 - Earnings Per Share - Computation of Basic and Diluted Earnings per Share (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended							6 Months Ended	9 Months Ended
	Jun. 30, 2023 USD ($) shares	Jun. 20, 2023 shares	Sep. 30, 2023 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) $ / shares shares	Jun. 30, 2023 USD ($) shares	Mar. 31, 2023 USD ($)	Sep. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Jun. 20, 2023 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) item $ / shares shares	Sep. 30, 2022 USD ($) $ / shares shares
EARNINGS PER SHARE
Net income | $			$ 19,462		$ 7,556	$ 25,257	$ 26,905	$ 33,280	$ 41,471	$ 31,382	$ 52,275	$ 101,656
Weighted average shares used to compute basic EPS (in shares)							44,085,000			44,344,000		44,179,000
Weighted average shares used to compute diluted EPS (in shares)							44,543,000			44,752,000		44,747,000
Basic (in dollars per share) | $ / shares			$ 0.41				$ 0.61			$ 0.71	$ 1.15	$ 2.30
Diluted (in dollars per share) | $ / shares			$ 0.40				$ 0.60			$ 0.70	$ 1.14	$ 2.27
Ratio of participation in earnings for common stock and preferred stock										1
Share in dividends for unvested restricted stock awards with common shares | item											1
Restricted Stock Units
EARNINGS PER SHARE
Antidilutive shares										684,151
Performance Stock Units
EARNINGS PER SHARE
Antidilutive shares		248,706					248,706			248,706
Employee Stock Option [Member]
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)							458,000			381,000		560,000
Restricted Stock Units
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)												8,000
Antidilutive shares							248,706
Performance Stock Units
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)										27,000
Class A Common Stock
EARNINGS PER SHARE
Net income | $			$ 17,288	$ 18,616
Weighted average shares used to compute basic EPS (in shares)			42,144,000	42,044,000
Weighted average shares used to compute diluted EPS (in shares)			42,883,000	42,708,000
Basic (in dollars per share) | $ / shares			$ 0.41	$ 0.44
Diluted (in dollars per share) | $ / shares			$ 0.40	$ 0.44
Class A Common Stock | Restricted Stock Units
EARNINGS PER SHARE
Antidilutive shares				165,803
Class A Common Stock | Performance Stock Units
EARNINGS PER SHARE
Antidilutive shares				153,452
Class A Common Stock | Employee Stock Option [Member]
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)			352,000	339,000
Class A Common Stock | Restricted Stock
EARNINGS PER SHARE
Unvested restricted stock	1,900,000		1,800,000	1,800,000	1,900,000						1,800,000
Class A Common Stock | Restricted Stock Units
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)			85,000	62,000
Class A Common Stock | Performance Stock Units
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)			302,000	263,000
Class B Common Stock
EARNINGS PER SHARE
Net income | $			$ 1,395	$ 1,395
Weighted average shares used to compute basic EPS (in shares)			8,432,000	8,412,000
Weighted average shares used to compute diluted EPS (in shares)			8,686,000	8,642,000
Basic (in dollars per share) | $ / shares			$ 0.17	$ 0.17
Diluted (in dollars per share) | $ / shares			$ 0.16	$ 0.16
Class B Common Stock | Performance Stock Units
EARNINGS PER SHARE
Antidilutive shares		49,737		30,688
Class B Common Stock | Employee Stock Option [Member]
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)			103,000	97,000
Class B Common Stock | Restricted Stock
EARNINGS PER SHARE
Unvested restricted stock			400,000	400,000							400,000
Class B Common Stock | Restricted Stock Units
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)			49,000	41,000
Class B Common Stock | Performance Stock Units
EARNINGS PER SHARE
Dilutive effect of stock-based awards (in shares)			102,000	92,000
Class A Restricted Stock
EARNINGS PER SHARE
Net income | $			$ 721	$ 824
Class B Restricted Stock
EARNINGS PER SHARE
Net income | $	$ 58			$ 58