Loans - Summary of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Accounts Notes And Loans Receivable [Line Items]
Total loans	$ 4,795,879	$ 4,535,885
Premiums, discounts and deferred fees and expenses	9,634	11,748
Loans, net of deferred fees	4,805,513	4,547,633
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Loans, net of deferred fees	793,314
Commercial and Industrial Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans	696,596	600,213
Loans, net of deferred fees	698,870
Consumer Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans	17,476	16,273
Loans, net of deferred fees	17,562
Real Estate Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans	4,081,807	3,919,399
Real Estate Loans | Residential Properties
Accounts Notes And Loans Receivable [Line Items]
Total loans	3,220,524	3,015,100
Loans, net of deferred fees	3,227,741
Real Estate Loans | Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans	793,182	834,042
Loans, net of deferred fees	793,315
Real Estate Loans | Land
Accounts Notes And Loans Receivable [Line Items]
Total loans	68,101	70,257
Loans, net of deferred fees	68,025
Multifamily | Real Estate Loans | Residential Properties
Accounts Notes And Loans Receivable [Line Items]
Total loans	2,369,081	2,143,919
Single Family | Real Estate Loans | Residential Properties
Accounts Notes And Loans Receivable [Line Items]
Total loans	$ 851,443	$ 871,181