Condensed Statements of Stockholders' Equity (Unaudited) - USD ($)		Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balances (in shares) at Dec. 31, 2022		36,765,000
Balances at Dec. 31, 2022		$ 368,000	$ 779,602,000	$ (341,207,000)	$ 0	$ 438,763,000
Net income		0	0	3,530,000	0	3,530,000
Unrealized loss on available-for-sale securities						0
Cash dividends declared		$ 0	(18,807,000)	0	0	(18,807,000)
Stock based awards and amortization (in shares)		4,000
Stock based awards and amortization		$ 0	181,000		0	181,000
Issuance of common stock pursuant to public offerings, net (in shares)		2,690,000
Issuance of common stock pursuant to public offerings, net		$ 26,000	31,631,000	0	0	31,657,000
Shares repurchased and retired (in shares)		(373,000)
Shares repurchased and retired		$ (3,000)	(3,960,000)	0	0	$ (3,963,000)
Balances (in shares) at Mar. 31, 2023		39,086,000				39,086,000
Balances at Mar. 31, 2023		$ 391,000	788,647,000	(337,677,000)	0	$ 451,361,000
Balances (in shares) at Dec. 31, 2022		36,765,000
Balances at Dec. 31, 2022		$ 368,000	779,602,000	(341,207,000)	0	$ 438,763,000
Issuance of common stock pursuant to public offerings, net (in shares)	[1]					15,880,039
Issuance of common stock pursuant to public offerings, net	[2]					$ 159,438,000
Balances (in shares) at Dec. 31, 2023		51,636,000
Balances at Dec. 31, 2023		$ 516,000	849,845,000	(380,433,000)	17,000	469,945,000
Net income		0	0	19,776,000	0	19,776,000
Unrealized loss on available-for-sale securities		0	0	0	(47,000)	(47,000)
Cash dividends declared		$ 0	(18,724)	0	0	(18,724)
Stock based awards and amortization (in shares)		33,000
Stock based awards and amortization		$ 0	350,000		0	$ 350,000
Issuance of common stock pursuant to public offerings, net (in shares)		1,490,000				1,490,075	[1]
Issuance of common stock pursuant to public offerings, net		$ 15,000	13,094,000	0	0	$ 13,109,000	[2]
Shares repurchased and retired (in shares)		(333,000)
Shares repurchased and retired		$ (3,000)	(2,775,000)	0	0	$ (2,778,000)
Balances (in shares) at Mar. 31, 2024		52,826,000				52,826,000
Balances at Mar. 31, 2024		$ 528,000	$ 841,790,000	$ (360,657,000)	$ (30,000)	$ 481,631,000

[1] The Company has entered into eleven equity distribution agreements, ten of which have either been terminated because all shares were sold or were replaced with a subsequent agreement.

[2] Net proceeds are net of the underwriters' discount, if applicable, and other offering costs.