Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Capital Surplus	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning Balance at Dec. 31, 2020	$ 3,016,948	$ 55,057	$ 1,090,450	$ 1,891,246	$ 318,340	$ (338,145)
Total comprehensive income (loss)	84,822			180,055	(95,233)
Dividends	(31,167)			(31,167)
Purchase of treasury stock	(4,088)					(4,088)
Issuances of equity awards, net of forfeitures	695		(4,122)			4,817
Recognition of equity-based compensation	8,609		8,609
Sale of treasury stock	301		148			153
Exercise of stock options	14,124		3,054			11,070
Ending Balance at Jun. 30, 2021	3,090,244	55,057	1,098,139	2,040,134	223,107	(326,193)
Beginning Balance at Mar. 31, 2021	2,958,239	55,057	1,093,667	1,968,318	169,197	(328,000)
Total comprehensive income (loss)	141,322			87,412	53,910
Dividends	(15,596)			(15,596)
Purchase of treasury stock	(61)					(61)
Issuances of equity awards, net of forfeitures			(79)			79
Recognition of equity-based compensation	4,152		4,152
Sale of treasury stock	150		83			67
Exercise of stock options	2,038		316			1,722
Ending Balance at Jun. 30, 2021	3,090,244	55,057	1,098,139	2,040,134	223,107	(326,193)
Beginning Balance at Dec. 31, 2021	3,145,424	55,057	1,110,520	2,176,998	126,314	(323,465)
Total comprehensive income (loss)	(447,598)			243,519	(691,117)
Dividends	(36,063)			(36,063)
Purchase of treasury stock	(31,806)					(31,806)
Issuances of equity awards, net of forfeitures	679		(6,630)			7,309
Recognition of equity-based compensation	11,223		11,223
Sale of treasury stock	285		174			111
Exercise of stock options	744		217			527
Ending Balance at Jun. 30, 2022	2,642,888	55,057	1,115,504	2,384,454	(564,803)	(347,324)
Beginning Balance at Mar. 31, 2022	2,748,405	55,057	1,109,585	2,265,129	(343,128)	(338,238)
Total comprehensive income (loss)	(84,119)			137,556	(221,675)
Dividends	(18,231)			(18,231)
Purchase of treasury stock	(9,319)					(9,319)
Recognition of equity-based compensation	5,738		5,738
Sale of treasury stock	147		90			57
Exercise of stock options	267		91			176
Ending Balance at Jun. 30, 2022	$ 2,642,888	$ 55,057	$ 1,115,504	$ 2,384,454	$ (564,803)	$ (347,324)