CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Series E	Series F	Series A	Class C non-voting common stock	Series D	Series B	Preferred Stock	Preferred Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Preferred Stock Series E	Preferred Stock Series F	Preferred Stock Series A	Preferred Stock Series D	Preferred Stock Series B	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, 2017										8,400							10,619
Beginning balance at Dec. 31, 2017	$ 708,644									$ 204,759							$ 10,619			$ 118,979			$ 51,112		$ 323,175
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	108,080																								108,080
Other comprehensive loss, net of tax	(26,156)																						(26,156)
Cash dividends, preferred stock	(13,182)																								(13,182)
Cash dividends, common stock	(24,722)																								(24,722)
Issuance of stock (in shares)																			50
Issuance of stock							$ 57												$ 50			$ 7
Loss on retirement of preferred stock	0
Stock-based compensation cost	2,518																			2,518
Other stock-based award activity	(2,682)																			(2,682)
Ending balance (in shares) at Dec. 31, 2018										8,400							10,669
Ending 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	109,546																								109,546
Other comprehensive loss, net of tax	(41,117)																						(41,117)
Cash dividends, preferred stock	(13,940)																								(13,940)
Cash dividends, common stock	(29,954)																								(29,954)
Issuance of stock (in shares)															4,000				43
Issuance of stock							87	$ 96,659							$ 96,659				$ 43			44
Redemption of preferred stock (in shares)																3,000
Redemption of preferred stock									$ (73,044)							$ (73,044)
Loss on retirement of preferred stock	(1,956)																								(1,956)
Stock-based compensation cost	2,258																			2,258
Other stock-based award activity	$ (1,820)																			(1,820)
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	108,648																								108,648
Other comprehensive loss, net of tax	2,238																						2,238
Cash dividends, preferred stock	(17,805)																								(17,805)
Cash dividends, common stock	(34,333)																								(34,333)
Issuance of stock (in shares)												3,180	4,800						29
Issuance of stock				$ 77,003	$ 116,160		85					$ 77,003	$ 116,160						$ 29			$ 56
Repurchase of Class C Common Stock (in shares)																			(4)
Treasury Stock, Value, Acquired, Cost Method							$ (235)												$ (4)									$ (231)
Redemption of preferred stock (in shares)														2,400
Redemption of preferred stock						$ (58,333)								$ (58,333)
Loss on retirement of preferred stock	(1,667)																								(1,667)
Stock-based compensation cost	4,128																			4,128
Other stock-based award activity	(589)																			(589)
Ending balance (in shares) at Dec. 31, 2020										14,980							10,737
Ending balance at Dec. 31, 2020	$ 992,477									$ 363,204							$ 10,737			$ 122,899			$ (13,923)		$ 509,560