CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Class C non-voting common stock	Preferred Stock	Preferred Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock Class C non-voting common stock	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjusted Balance	Additional Paid-in Capital Class C non-voting common stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings Cumulative Effect, Period of Adoption, Adjusted Balance	Retained Earnings Class C non-voting common stock
Beginning balance ( in shares) at Dec. 31, 2019					9,400	9,400	10,712	10,712
Beginning balance at Dec. 31, 2019	$ 799,276	$ (2,099)	$ 797,177		$ 228,374	$ 228,374	$ 10,712	$ 10,712		$ 119,304	$ 119,304		$ (16,161)	$ (16,161)	$ 457,047	$ (2,099)	$ 454,948
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	12,830														12,830
Other comprehensive loss, net of tax	(105,276)												(105,276)
Cash dividends, preferred stock	(3,431)														(3,431)
Cash dividends, common stock	(8,571)														(8,571)
Issuance of common stock (in shares)									15
Issuance of common stock				$ 34					$ 15			$ 19
Repurchase of Class C Common Stock (in shares)									(4)
Repurchase of Class C Common Stock				(235)					$ (4)									$ (231)
Stock-based compensation cost	1,293									1,293
Other stock-based award activity	(204)									(204)
Ending balance (in shares) at Mar. 31, 2020					9,400		10,723
Ending balance at Mar. 31, 2020	693,617				$ 228,374		$ 10,723			120,412			(121,437)		455,545
Beginning balance ( in shares) at Dec. 31, 2020					14,980		10,737
Beginning balance at Dec. 31, 2020	992,477				$ 363,204		$ 10,737			122,899			(13,923)		509,560
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	33,227														33,227
Other comprehensive loss, net of tax	65,667												65,667
Cash dividends, preferred stock	(5,269)														(5,269)
Cash dividends, common stock	(9,450)														(9,450)
Issuance of common stock (in shares)									21
Issuance of common stock				$ 33					$ 21			$ 12
Stock-based compensation cost	1,665									1,665
Other stock-based award activity	(858)									(858)
Ending balance (in shares) at Mar. 31, 2021					14,980		10,758
Ending balance at Mar. 31, 2021	$ 1,077,492				$ 363,204		$ 10,758			$ 123,718			$ 51,744		$ 528,068