Income Taxes - Deferred Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Net operating and built-in-loss carryforward	$ 5,736	$ 7,823
Purchase accounting adjustment - loans	11,814	15,850
Allowance for credit losses	35,542	14,796
Compensation and benefits	22,513	17,723
Legal and other reserves	7,097	1,272
Foreclosed property	1,913	5,456
Operating lease liabilities	29,348	29,125
Other	9,717	6,475
Deferred tax assets	123,680	98,520
Deferred tax liabilities:
Premises and equipment	20,076	10,079
Intangible assets	4,518	6,098
Derivatives	17,688	4,342
Loan servicing	34,868	13,278
Operating lease ROU assets	24,755	26,498
Other	8,015	5,251
Deferred tax liabilities	109,920	65,546
Net deferred tax asset	$ 13,760	$ 32,974