Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($)	Total	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance, shares at Dec. 31, 2021		14,145,888
Common stock repurchased, shares	(1,207,688)	(1,207,688)
Restricted stock units converted to common stock, shares		3,980
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		33,275
Balance, shares at Jun. 30, 2022		12,975,455
Balance at Dec. 31, 2021	$ 1,824,200,000	$ 100,000	$ 197,200,000	$ 1,626,700,000	$ 200,000
Net income	321,700,000	0	0	321,700,000	0
Other comprehensive loss	(2,400,000)	0	0	0	(2,400,000)
Stock-based compensation	18,200,000	0	18,200,000	0	0
Common stock repurchased, value	(652,700,000)	0	(700,000)	(652,000,000.0)	0
Stock Issued During Period, Value, Stock Options Exercised	11,100,000		11,100,000
Balance at Jun. 30, 2022	$ 1,520,100,000	$ 100,000	225,800,000	1,296,400,000	(2,200,000)
Balance, shares at Mar. 31, 2022		13,363,783
Common stock repurchased, shares	(403,953)	(403,953)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		15,625
Balance, shares at Jun. 30, 2022		12,975,455
Balance at Mar. 31, 2022	$ 1,628,800,000	$ 100,000	211,500,000	1,418,700,000	(1,500,000)
Net income	107,400,000	0	0	107,400,000	0
Other comprehensive loss	(700,000)	0	0	0	(700,000)
Stock-based compensation	9,100,000	0	9,100,000	0	0
Common stock repurchased, value	(229,700,000)	0	0	(229,700,000)	0
Stock Issued During Period, Value, Stock Options Exercised	5,200,000		5,200,000
Balance at Jun. 30, 2022	$ 1,520,100,000	$ 100,000	225,800,000	1,296,400,000	(2,200,000)
Balance, shares at Dec. 31, 2022	12,756,885	12,756,885
Common stock repurchased, shares	(49,261)	(49,261)
Restricted stock units converted to common stock, shares		101,757
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		12,300
Balance, shares at Jun. 30, 2023	12,821,681	12,821,681
Balance at Dec. 31, 2022	$ 1,624,000,000	$ 100,000	245,700,000	1,381,100,000	(2,900,000)
Net income	121,700,000	0	0	121,700,000	0
Other comprehensive loss	200,000	0	0	0	200,000
Stock-based compensation	19,700,000	0	19,700,000	0	0
Common stock repurchased, value	(22,700,000)	0	(7,800,000)	(14,900,000)	0
Stock Issued During Period, Value, Stock Options Exercised	4,100,000		4,100,000
Balance at Jun. 30, 2023	$ 1,747,000,000	$ 100,000	261,700,000	1,487,900,000	(2,700,000)
Balance, shares at Mar. 31, 2023		12,836,907
Common stock repurchased, shares	(16,226)	(16,226)
Restricted stock units converted to common stock, shares		1,000
Balance, shares at Jun. 30, 2023	12,821,681	12,821,681
Balance at Mar. 31, 2023	$ 1,723,400,000	$ 100,000	252,100,000	1,473,300,000	(2,100,000)
Net income	22,200,000	0	0	22,200,000	0
Other comprehensive loss	(600,000)	0	0	0	(600,000)
Stock-based compensation	9,800,000	0	9,800,000	0	0
Common stock repurchased, value	(7,800,000)	0	(200,000)	(7,600,000)	0
Balance at Jun. 30, 2023	$ 1,747,000,000	$ 100,000	$ 261,700,000	$ 1,487,900,000	$ (2,700,000)