Acquired Loans - Changes in the Carrying Value of Acquired Loans (Details) - USD ($) $ in Thousands		9 Months Ended		12 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning		$ 71,786
Accretion to interest income			$ 4,290
Carrying value, net, ending				$ 71,786
Acquired Not ASC 310-30 [Member]
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning	[1]	0	2,811	2,811
Transfers	[1],[2]			(2,926)
Accretion to interest income	[1]	0		115
Payments received, net	[1]	0		0
Other	[1],[3]	0		0
Change in allowance for loan losses, acquired loans	[1]	0		0
Carrying value, net, ending	[1]	0		0
Acquired Not ASC 310-30 [Member] | Cumulative Effect Period Of Adoption Adjustment [Member] | ASU 2016-13 [Member]
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning	[1]	0
Carrying value, net, ending	[1]			0
Acquired Impaired [Member]
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning		$ 71,786	$ 102,890	102,890
Accounting Standards Update [Extensible List]		us-gaap:AccountingStandardsUpdate201613Member
Transfers	[2]			0
Accretion to interest income		$ 0		5,532
Payments received, net		0		(37,230)
Other	[3]	0		178
Change in allowance for loan losses, acquired loans		0		416
Carrying value, net, ending		0		71,786
Acquired Impaired [Member] | Cumulative Effect Period Of Adoption Adjustment [Member] | ASU 2016-13 [Member]
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning		$ (71,786)
Carrying value, net, ending				$ (71,786)

[1] “Acquired Not ASC 310-30” loans consist of loans that are not in scope for FASB ASC Subtopic 310-30.

[2] “Acquired Not ASC 310-30” loans transferred to LHFI due to the discount on these loans being fully amortized.

[3] Includes miscellaneous timing adjustments as well as acquired loan terminations through foreclosure, charge-off and other terminations.