Loans and Allowance for Loan Losses - Rollforward of Purchase Credit Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Gross Carrying Value
Gross carrying value, beginning balance	$ 29,544	$ 42,837
Acquisitions		1,883
Business Combination Acquired Receivable Gross Contractual Transfer	0	0
Year-to-date settlements	8,158	15,176
Gross carrying value, ending balance	21,386	29,544
Accretable Yield
Accretable yield, beginning balance	4,801	114
Acquisitions		0
Reclassification of yield from nonaccretable to accretable		(7,505)
Reclassification of discount to allowance for credit losses	0
Year-to-date settlements	2,561	2,818
Accretable yield, ending balance	2,240	4,801
Nonaccretable Yield [Abstract]
Acquired Nonaccretable Yield		0
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications to Nonaccretable Difference	3,828	7,505
Certain Loans Acquired in Transfer, Nonaccretable Difference, Settlements	0	6,061
Certain Loans Acquired in Transfer, Nonaccretable Difference	0	(3,828)	$ (17,394)
Net Carrying Value
Net carrying value, beginning balance	20,915	25,329
Acquisitions		1,883
Reclassification of yield from nonaccretable to accretable	3,828	0
Settlements	(5,597)	(6,297)
Net carrying value, ending balance	$ 19,146	$ 20,915