PARENT COMPANY STATEMENTS - Condensed Statements of Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets:
Cash and cash equivalents	$ 1,875,064	$ 1,645,805
Investment in and advances to:
Other assets	313,854	281,903
Total assets	15,552,657	13,931,094	$ 11,410,295
Liabilities and shareholders' equity:
Accrued interest and other liabilities	210,797	230,724
Borrowings	0	77,320
Shareholders' equity	2,100,807	2,104,107	$ 1,855,234	$ 1,713,783
Total liabilities and shareholders' equity	15,552,657	13,931,094
Parent Company
Assets:
Cash and cash equivalents	154,374	196,021
Investment securities	8,679	6,043
Investment in and advances to:
Bank subsidiary	1,721,520	1,802,150
Non-bank subsidiaries	232,096	196,090
Other assets	18,462	15,290
Total assets	2,135,131	2,215,594
Liabilities and shareholders' equity:
Accrued interest and other liabilities	31,047	30,864
Borrowings	3,277	80,623
Shareholders' equity	2,100,807	2,104,107
Total liabilities and shareholders' equity	$ 2,135,131	$ 2,215,594