Income Taxes - Tax Effects of Temporary Differences Related to Deferred Taxes Included in Other Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Loans acquired	$ 10,100	$ 20,783
Allowance for credit losses	58,028	16,732
Valuation of foreclosed assets	1,673	2,626
Tax NOLs from acquisition	16,028	18,118
Deferred compensation payable	3,060	2,750
Accrued equity and other compensation	5,905	6,677
Acquired securities	587	3,393
Right-of-use lease liability	7,835	10,221
Allowance for unfunded commitments	5,583	0
Other	7,600	7,886
Gross deferred tax assets	116,399	89,186
Deferred tax liabilities:
Goodwill and other intangible amortization	(38,882)	(41,221)
Accumulated depreciation	(34,667)	(36,554)
Right-of-use lease asset	(7,813)	(10,176)
Unrealized gain on available-for-sale securities	(17,521)	(3,720)
Other	(4,021)	(7,651)
Gross deferred tax liabilities	(102,904)	(99,322)
Net deferred tax asset (liability)	$ 13,495
Net deferred tax asset (liability)		$ (10,136)