CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Common Stock and Paid in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Balance, beginning of the period (in shares) at Dec. 31, 2020		35,159,200
Balance, beginning of the period at Dec. 31, 2020	$ 1,666,264		$ 1,349,879	$ 247,316	$ 69,069
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	46,855			46,855
Other comprehensive loss, net of income tax	(56,103)				(56,103)
Accrual of dividends on common stock	(14,589)			(14,589)
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered (in shares)		76,143
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered	1,714		1,714
Repurchase of common stock (in shares)		(500,000)
Repurchase of common stock	(25,324)		(25,324)
Balance, end of the period (in shares) at Mar. 31, 2021		34,735,343
Balance, end of the period at Mar. 31, 2021	$ 1,618,817		1,326,269	279,582	12,966
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative dividends declared per common share	$ 0.41
Balance, beginning of the period (in shares) at Dec. 31, 2020		35,159,200
Balance, beginning of the period at Dec. 31, 2020	$ 1,666,264		1,349,879	247,316	69,069
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	101,237
Balance, end of the period (in shares) at Jun. 30, 2021		34,550,888
Balance, end of the period at Jun. 30, 2021	$ 1,669,211		1,311,455	319,505	38,251
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative dividends declared per common share	$ 0.82
Balance, beginning of the period (in shares) at Mar. 31, 2021		34,735,343
Balance, beginning of the period at Mar. 31, 2021	$ 1,618,817		1,326,269	279,582	12,966
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	54,382			54,382
Other comprehensive loss, net of income tax	25,285				25,285
Accrual of dividends on common stock	(14,459)			(14,459)
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered (in shares)		65,545
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered	(259)		(259)
Repurchase of common stock (in shares)		(250,000)
Repurchase of common stock	(14,555)		(14,555)
Balance, end of the period (in shares) at Jun. 30, 2021		34,550,888
Balance, end of the period at Jun. 30, 2021	$ 1,669,211		1,311,455	319,505	38,251
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative dividends declared per common share	$ 0.41
Net income	$ 49,884			49,884
Other comprehensive loss, net of income tax	(23,312)				(23,312)
Accrual of dividends on common stock	(14,354)			(14,354)
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered (in shares)		1,103
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered	2,339		2,339
Repurchase of common stock (in shares)		(300,000)
Repurchase of common stock	(16,649)		(16,649)
Balance, end of the period (in shares) at Sep. 30, 2021		34,251,991
Balance, end of the period at Sep. 30, 2021	1,667,119		1,297,145	355,035	14,939
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	49,927			49,927
Other comprehensive loss, net of income tax	(14,755)				(14,755)
Accrual of dividends on common stock	(14,200)			(14,200)
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered (in shares)		641
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered	2,236		2,236
Balance, end of the period (in shares) at Dec. 31, 2021		34,252,632
Balance, end of the period at Dec. 31, 2021	$ 1,690,327		1,299,381	390,762	184
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative dividends declared per common share	$ 0.41
Net income	$ 43,963			43,963
Other comprehensive loss, net of income tax	(154,275)				(154,275)
Accrual of dividends on common stock	(15,066)			(15,066)
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered (in shares)		120,152
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered	(1,169)		(1,169)
Balance, end of the period (in shares) at Mar. 31, 2022		34,372,784
Balance, end of the period at Mar. 31, 2022	$ 1,563,780		1,298,212	419,659	(154,091)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative dividends declared per common share	$ 0.44
Balance, beginning of the period (in shares) at Dec. 31, 2021		34,252,632
Balance, beginning of the period at Dec. 31, 2021	$ 1,690,327		1,299,381	390,762	184
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	91,928
Balance, end of the period (in shares) at Jun. 30, 2022		34,191,330
Balance, end of the period at Jun. 30, 2022	$ 1,485,830		1,289,499	452,246	(255,915)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative dividends declared per common share	$ 0.88
Balance, beginning of the period (in shares) at Mar. 31, 2022		34,372,784
Balance, beginning of the period at Mar. 31, 2022	$ 1,563,780		1,298,212	419,659	(154,091)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	47,965			47,965
Other comprehensive loss, net of income tax	(101,824)				(101,824)
Accrual of dividends on common stock	(15,378)			(15,378)
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered (in shares)		18,546
Amortization of stock-based compensation related to restricted stock grants, net of shares surrendered	2,247		2,247
Repurchase of common stock (in shares)		(200,000)
Repurchase of common stock	(10,960)		(10,960)
Balance, end of the period (in shares) at Jun. 30, 2022		34,191,330
Balance, end of the period at Jun. 30, 2022	$ 1,485,830		$ 1,289,499	$ 452,246	$ (255,915)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative dividends declared per common share	$ 0.44