Parent Company Information (Components of Condensed Balance Sheets The Parent Company) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets:
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 461,570	$ 263,104	$ 257,895	$ 329,499
Intercompany debt securities		150,000
Other assets	531,469	626,551
Total Assets	34,915,599	32,590,690
Liabilities and shareholders’ equity:
Liabilities	31,477,274	29,356,065
Total liabilities and shareholders' equity	34,915,599	32,590,690
Parent Company [Member]
Assets:
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	316,193	302,315	$ 510,940	$ 317,473
Intercompany debt securities	150,000
Investment in subsidiaries	3,526,782	3,340,556
Alternative investments	20,163	8,970
Other assets	3,953	8,122
Total Assets	4,017,091	3,809,963
Liabilities and shareholders’ equity:
Senior notes	485,611	490,343
Junior subordinated debt	77,320	77,320
Accrued interest payable	5,861	5,862
Due to subsidiaries	488	324
Other liabilities	9,486	1,489
Liabilities	578,766	575,338
Shareholders’ equity	3,438,325	3,234,625
Total liabilities and shareholders' equity	$ 4,017,091	$ 3,809,963