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	Series E Preferred Stock	5.700% Non-Cumulative Preferred Stock, Series D	Series B Preferred Stock	Preferred Stock	Preferred Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Preferred Stock Series E Preferred Stock	Preferred Stock 5.700% Non-Cumulative Preferred Stock, Series D	Preferred Stock Series B Preferred Stock	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, 2018								8,400					10,669
Beginning balance at Dec. 31, 2018	$ 752,557							$ 204,759					$ 10,669			$ 118,822			$ 24,956		$ 393,351
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	25,170																				25,170
Other comprehensive loss, net of tax	(3,702)																		(3,702)
Cash dividends, preferred stock	(3,296)																				(3,296)
Cash dividends, common stock	(7,470)																				(7,470)
Issuance of stock (in shares)															20
Issuance of stock				$ 23											$ 20			$ 3
Stock-based compensation cost	724															724
Other stock-based award activity	(708)															(708)
Ending balance (in shares) at Mar. 31, 2019								8,400					10,689
Ending balance at Mar. 31, 2019	763,298							$ 204,759					$ 10,689			118,841			21,254		407,755
Beginning balance ( in shares) at Dec. 31, 2018								8,400					10,669
Beginning balance at Dec. 31, 2018	752,557							$ 204,759					$ 10,669			118,822			24,956		393,351
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	59,215
Other comprehensive loss, net of tax	(37,799)
Loss on retirement of preferred stock	(1,956)
Ending balance (in shares) at Jun. 30, 2019								9,400					10,700
Ending balance at Jun. 30, 2019	773,742							$ 228,374					$ 10,700			118,942			(12,843)		428,569
Beginning balance ( in shares) at Dec. 31, 2018								8,400					10,669
Beginning balance at Dec. 31, 2018	752,557							$ 204,759					$ 10,669			118,822			24,956		393,351
Ending balance (in shares) at Dec. 31, 2019								9,400	9,400				10,712	10,712
Ending 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
Beginning balance ( in shares) at Mar. 31, 2019								8,400					10,689
Beginning balance at Mar. 31, 2019	763,298							$ 204,759					$ 10,689			118,841			21,254		407,755
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	34,045																				34,045
Other comprehensive loss, net of tax	(34,097)																		(34,097)
Cash dividends, preferred stock	(3,785)																				(3,785)
Cash dividends, common stock	(7,490)																				(7,490)
Issuance of stock (in shares)											4,000				11
Issuance of stock				14		$ 96,659					$ 96,659				$ 11			3
Redemption of stock (in shares)												(3,000)
Redemption of stock							$ (73,044)					$ (73,044)
Loss on retirement of preferred stock	(1,956)																				(1,956)
Stock-based compensation cost	533															533
Other stock-based award activity	(435)															(435)
Ending balance (in shares) at Jun. 30, 2019								9,400					10,700
Ending balance at Jun. 30, 2019	773,742							$ 228,374					$ 10,700			118,942			(12,843)		428,569
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 stock (in shares)															15
Issuance of 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, 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	48,456
Other comprehensive loss, net of tax	(75,336)
Loss on retirement of preferred stock	0
Ending balance (in shares) at Jun. 30, 2020								12,580					10,733
Ending balance at Jun. 30, 2020	$ 824,116							$ 305,377					$ 10,733			120,856			(91,497)		478,647
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Beginning balance ( in shares) at Mar. 31, 2020								9,400					10,723
Beginning balance at Mar. 31, 2020	$ 693,617							$ 228,374					$ 10,723			120,412			(121,437)		455,545
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	35,626																				35,626
Other comprehensive loss, net of tax	29,940																		29,940
Cash dividends, preferred stock	(3,939)																				(3,939)
Cash dividends, common stock	(8,585)																				(8,585)
Issuance of stock (in shares)										3,180					10
Issuance of stock				$ 27	$ 77,003					$ 77,003					$ 10			$ 17
Loss on retirement of preferred stock	0
Stock-based compensation cost	719
Other stock-based award activity	(292)															(292)
Ending balance (in shares) at Jun. 30, 2020								12,580					10,733
Ending balance at Jun. 30, 2020	$ 824,116							$ 305,377					$ 10,733			$ 120,856			$ (91,497)		$ 478,647