Income Taxes - Tax Effects of Temporary Differences Related to Deferred Taxes Included in Other Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Deferred tax assets:
Loans acquired	$ 5,882	$ 10,100
Allowance for credit losses	47,652	58,028
Valuation of foreclosed assets	1,631	1,673
Tax NOLs from acquisition	13,698	16,028
Deferred compensation payable	3,342	3,060
Accrued equity and other compensation	6,091	5,905
Acquired securities	431	587
Right-of-use lease liability	9,992	7,835
Unrealized loss on AFS securities	3,631	0
Allowance for unfunded commitments	5,444	5,583
Other	8,255	7,600
Gross deferred tax assets	106,049	116,399
Deferred tax liabilities:
Goodwill and other intangible amortization	(36,584)	(38,882)
Accumulated depreciation	(24,510)	(34,667)
Right-of-use lease asset	(9,893)	(7,813)
Unrealized gain on available-for-sale securities	0	(17,521)
Other	(4,001)	(4,021)
Gross deferred tax liabilities	(74,988)	(102,904)
Net deferred tax asset	$ 31,061	$ 13,495