CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Impact of ASU 2016-13 adoption on January 1, 2020	Adjusted balance at January 1, 2020	Series D Preferred Stock	Preferred Stock	Preferred Stock	Preferred Stock Adjusted balance at January 1, 2020	Preferred Stock Series D Preferred Stock	Common Stock	Common Stock Adjusted balance at January 1, 2020	Capital Surplus	Capital Surplus Adjusted balance at January 1, 2020	Retained Earnings	Retained Earnings Impact of ASU 2016-13 adoption on January 1, 2020	Retained Earnings Adjusted balance at January 1, 2020	Retained Earnings Series D Preferred Stock	Retained Earnings     Preferred Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Other Comprehensive Income (Loss) Adjusted balance at January 1, 2020	Treasury Stock	Treasury Stock Adjusted balance at January 1, 2020
Balance at beginning of period at Dec. 31, 2017	$ 991,457					$ 938			$ 29,953		$ 503,709		$ 481,331					$ (24,474)		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	110,103												116,998					(6,895)
Reclassification of unrealized net gain on equity securities													280					(280)
Cash dividends declared:
Preferred	(39)															$ (39)
Cash dividends per share preferred stock (in dollars per share)				$ 52.50
Common	(19,318)												(19,318)
Redemption of preferred stock	(938)							$ (938)
Purchase of shares of treasury stock	(97)																			(97)
Issuance of shares of common stock	239,502								4,524		234,881									97
Stock based compensation	4,505										4,505
Balance at end of period at Dec. 31, 2018	1,325,175					0			34,477		743,095		579,252					(31,649)		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	$ 179,852												149,129					30,723
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Reclassification of unrealized net gain on equity securities	$ (1,272)												(1,272)
Cash dividends declared:
Common	(24,607)												(24,607)
Issuance of shares of common stock	92,919								2,227		90,692
Stock based compensation	6,070										6,070
Balance at end of period at Dec. 31, 2019	1,578,137	$ (14,891)	$ 1,563,246			0	$ 0		36,704	$ 36,704	839,857	$ 839,857	702,502	$ (14,891)	$ 687,611			(926)	$ (926)	0	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income (loss)	$ 211,583												137,938					73,645
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Cash dividends declared:
Preferred	$ (4,451)																$ (4,451)
Cash dividends per share preferred stock (in dollars per share)					$ 386.94
Common	(29,468)												(29,468)
Issuance of Series E preferred stock				$ 110,705				$ 110,705
Issuance of shares of common stock	220,206								5,390		214,816
Stock based compensation	7,410										7,410
Balance at end of period at Dec. 31, 2020	$ 2,079,231					$ 110,705			$ 42,094		$ 1,062,083		$ 791,630					$ 72,719		$ 0