Parent Company Information (Components of Condensed Income Statement The Parent Company) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating Income:
Total operating income	$ 479,361	$ 417,724	$ 524,492
Operating Expense:
Compensation and benefits	419,989	428,391	395,402
Non-interest expense	77,341	78,228	98,617
Income (loss) before income tax expense	533,861	279,974	486,692
Income tax benefit	(124,997)	(59,353)	(103,969)
Net income	408,864	220,621	382,723
Parent Company [Member]
Operating Income:
Dividend income from bank subsidiary	200,000	20,000	360,000
Interest on securities and deposits	3,444	5,530	10,728
Alternative investments income	13,033	2,467	(256)
Other non-interest income	75	634	382
Total operating income	216,552	28,631	370,854
Operating Expense:
Interest expense on borrowings	16,876	18,684	21,062
Non-interest expense	32,187	16,426	15,527
Total operating expense	49,063	35,110	36,589
Income (loss) before income tax expense	167,489	(6,479)	334,265
Income tax benefit	3,121	4,572	4,671
Equity in undistributed earnings of subsidiaries	238,254	222,528	43,787
Net income	$ 408,864	$ 220,621	$ 382,723