CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Capital Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Balance, beginning of period at Dec. 31, 2021		$ 18,730	$ 163,583	$ 981,825	$ (45,243)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued for vested restricted stock units, net of shares withheld for taxes		69	(10,820)
Shares issued for employee stock purchase plan		6	944
Shares issued to directors		7	(7)
Equity compensation expense			11,576
Net income	$ 49,321			49,321
Other comprehensive income (loss)	(80,138)				(80,138)
Balance, end of period at Sep. 30, 2022	1,089,853	18,812	165,276	1,031,146	(125,381)
Balance, beginning of period at Jun. 30, 2022		18,811	161,885	1,016,308	(90,433)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued for vested restricted stock units, net of shares withheld for taxes		1	(129)
Shares issued for employee stock purchase plan		0	0
Shares issued to directors		0	0
Equity compensation expense			3,520
Net income	14,838			14,838
Other comprehensive income (loss)	(34,948)				(34,948)
Balance, end of period at Sep. 30, 2022	1,089,853	18,812	165,276	1,031,146	(125,381)
Balance, beginning of period at Dec. 31, 2022	1,172,466	18,574	140,702	1,098,454	(85,264)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued for vested restricted stock units, net of shares withheld for taxes		35	(2,577)
Shares issued for employee stock purchase plan		0	0
Shares issued to directors		7	(7)
Equity compensation expense			10,874
Net income	33,394			33,394
Other comprehensive income (loss)	(3,580)				(3,580)
Balance, end of period at Sep. 30, 2023	1,210,612	18,616	148,992	1,131,848	(88,844)
Balance, beginning of period at Jun. 30, 2023		18,616	145,219	1,112,813	(71,031)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued for vested restricted stock units, net of shares withheld for taxes		0	(29)
Shares issued for employee stock purchase plan		0	0
Shares issued to directors		0	0
Equity compensation expense			3,802
Net income	19,035			19,035
Other comprehensive income (loss)	(17,813)				(17,813)
Balance, end of period at Sep. 30, 2023	$ 1,210,612	$ 18,616	$ 148,992	$ 1,131,848	$ (88,844)