Loans Receivable and Allowance for Credit Losses (Amortized Cost of Loans on Nonaccrual Status) (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Financing Receivable, Nonaccrual [Line Items]
Total nonaccrual loans with no related allowance for loan losses	$ 87,404
Commercial lending
Financing Receivable, Nonaccrual [Line Items]
Total nonaccrual loans with no related allowance for loan losses	69,684
Commercial lending | Commercial and industrial (“C&I”)
Financing Receivable, Nonaccrual [Line Items]
Total nonaccrual loans with no related allowance for loan losses	64,431
Commercial lending | Commercial real estate (“CRE”)
Financing Receivable, Nonaccrual [Line Items]
Total nonaccrual loans with no related allowance for loan losses	5,253
Commercial lending | Total CRE
Financing Receivable, Nonaccrual [Line Items]
Total nonaccrual loans with no related allowance for loan losses	5,253
Consumer lending
Financing Receivable, Nonaccrual [Line Items]
Total nonaccrual loans with no related allowance for loan losses	17,720
Consumer lending | HELOCs
Financing Receivable, Nonaccrual [Line Items]
Total nonaccrual loans with no related allowance for loan losses	6,511
Consumer lending | Total residential mortgage
Financing Receivable, Nonaccrual [Line Items]
Total nonaccrual loans with no related allowance for loan losses	15,229
Consumer lending | Other consumer
Financing Receivable, Nonaccrual [Line Items]
Total nonaccrual loans with no related allowance for loan losses	2,491
Single-family residential | Consumer lending | Real estate loan
Financing Receivable, Nonaccrual [Line Items]
Total nonaccrual loans with no related allowance for loan losses	$ 8,718