CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Preferred Stock [Member] Series A Nonconvertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]
BALANCE at Dec. 31, 2021	$ 1,099,914	$ 2	$ 491	$ 658,728	$ 500,212	$ (18,235)	$ (41,284)
BALANCE (in shares) at Dec. 31, 2021		200,000	49,065,924				1,365,648
Net income	49,970				49,970
Other comprehensive loss	(3,660)					(3,660)
Cash dividend	(14,246)				(14,246)
Issuance of common stock to employees	5,979			5,979
Issuance of common stock to employees (in shares)			47,748
Shares withheld for employee taxes	(7,896)			(7,896)
Shares withheld for employee taxes (in shares)			(22,347)
Issuance of common stock to Board of Directors and Scientific Advisory Board	730			730
Issuance of common stock to Board of Directors and Scientific Advisory Board (in shares)			5,630
Issuance of common stock to employees under an ESPP	509			509
Issuance of common stock to employees under an ESPP (in shares)			2,875
BALANCE at Mar. 31, 2022	1,131,300	$ 2	$ 491	658,050	535,936	(21,895)	$ (41,284)
BALANCE (in shares) at Mar. 31, 2022		200,000	49,099,830				1,365,648
BALANCE at Dec. 31, 2022	1,275,369	$ 2	$ 491	681,335	653,277	(18,452)	$ (41,284)
BALANCE (in shares) at Dec. 31, 2022		200,000	49,136,030				1,365,648
Net income	39,839				39,839
Other comprehensive loss	2,975					2,975
Cash dividend	(16,769)				(16,769)
Issuance of common stock to employees	3,854		$ 1	3,853
Issuance of common stock to employees (in shares)			126,846
Shares withheld for employee taxes	(7,181)			(7,181)
Shares withheld for employee taxes (in shares)			(51,703)
Cancellation of restricted stock awards			$ (5)	5
Cancellation of restricted stock awards (in shares)			(526,241)
Issuance of common stock to Board of Directors and Scientific Advisory Board	723			723
Issuance of common stock to Board of Directors and Scientific Advisory Board (in shares)			6,896
Issuance of common stock to employees under an ESPP	655			655
Issuance of common stock to employees under an ESPP (in shares)			5,639
BALANCE at Mar. 31, 2023	$ 1,299,465	$ 2	$ 487	$ 679,390	$ 676,347	$ (15,477)	$ (41,284)
BALANCE (in shares) at Mar. 31, 2023		200,000	48,697,467				1,365,648