Additional Cash Flow Information - Additional Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Significant Noncash Transactions [Line Items]
Interest paid	$ 123,995	$ 182,541	$ 122,801
Income taxes paid	47,777	51,999	25,718
Transfers of premises to premises held for sale	11,200	0	0
Transfers of other real estate owned to premises held for sale	4,163	0	0
Right-of-use lease assets obtained in exchange for lessee operating lease liabilities (adoption of ASU 2016-02)	0	32,757
Transfers of held-to-maturity to available-for-sale securities	0	216,373	0
Transfers of loans to other assets held for sale	114,925	259,939	0
Transfers of deposits to other liabilities held for sale	213,025	159,853	0
Transfers of loans to foreclosed assets held for sale
Other Significant Noncash Transactions [Line Items]
Real estate transferred	10,712	4,760	16,858
Transfers of premises to foreclosed assets and other real estate owned
Other Significant Noncash Transactions [Line Items]
Real estate transferred	$ 3,120	$ 647	$ 3,690