Loans - Summary of Delinquent and Nonaccrual Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	$ 25,847	$ 23,685
90 Days or More Past Due and Still Accruing	2,403	403
Nonaccrual Past Due and Still Accruing	20,592	12,867
Current	4,582,593	4,512,200
Loans, net of deferred fees	4,615,323	4,547,633
Total loans	$ 4,608,440	$ 4,535,885
Percentage of Total Loans Due 30-59 Days	0.03%	0.19%
Percentage of Total Loans Due 60-89 Days	0.03%	0.04%
Percentage of Total Loans Due 90 Days or More	0.05%	0.01%
Percentage of Total Loans Due Nonaccrual	0.45%	0.28%
Percentage of Total Loans	0.56%	0.52%
Residential Properties
Accounts Notes And Loans Receivable [Line Items]
Total loans	$ 2,902,611	$ 3,015,100
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans	770,964	834,042
Commercial and Industrial Loans
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	8,267	11,416
90 Days or More Past Due and Still Accruing	481
Nonaccrual Past Due and Still Accruing	6,306	8,714
Current	850,477	588,797
Total loans	858,744	600,213
Consumer Loans
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	16	25
Nonaccrual Past Due and Still Accruing	16
Current	18,383	16,248
Total loans	18,399	16,273
Land
Accounts Notes And Loans Receivable [Line Items]
Total loans	57,722	70,257
30-59 Days
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	1,575	8,392
30-59 Days | Commercial and Industrial Loans
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	442	695
30-59 Days | Consumer Loans
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual		22
60-89 Days
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	1,277	2,023
60-89 Days | Commercial and Industrial Loans
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	1,038	2,007
60-89 Days | Consumer Loans
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual		3
Real Estate Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans	3,731,297	3,919,399
Real Estate Loans | Residential Properties
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	14,478	1,845
90 Days or More Past Due and Still Accruing	1,922
Nonaccrual Past Due and Still Accruing	12,532	1,743
Current	2,888,133	3,013,255
Total loans	2,902,611	3,015,100
Real Estate Loans | Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	2,675	10,399
90 Days or More Past Due and Still Accruing		403
Nonaccrual Past Due and Still Accruing	1,738	2,410
Current	768,289	823,643
Total loans	770,964	834,042
Real Estate Loans | Land
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	411
Current	57,311	70,257
Total loans	57,722	70,257
Real Estate Loans | 30-59 Days | Residential Properties
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual		89
Real Estate Loans | 30-59 Days | Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	722	7,586
Real Estate Loans | 30-59 Days | Land
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	411
Real Estate Loans | 60-89 Days | Residential Properties
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	24	$ 13
Real Estate Loans | 60-89 Days | Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total Past Due and Nonaccrual	$ 215