Loans Receivable and Allowance for Credit Losses (Non-PCI TDR Modifications) (Details) - Non-PCI Loans - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	$ 48,273	$ 2,777	$ 77,705	$ 2,777
Principal
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	9,909	1,529	39,341	1,529
Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	837	0	837
Other (2)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	38,364	411	38,364	411
Commercial lending
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	48,054	837	77,486	837
Commercial lending | Principal
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	9,909	0	39,341	0
Commercial lending | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	837	0	837
Commercial lending | Other (2)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	38,145	0	38,145	0
Commercial lending | Commercial and industrial (“C&I”)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	48,054	0	77,486	0
Commercial lending | Commercial and industrial (“C&I”) | Principal
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	9,909	0	39,341	0
Commercial lending | Commercial and industrial (“C&I”) | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	0	0	0
Commercial lending | Commercial and industrial (“C&I”) | Other (2)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	38,145	0	38,145	0
Commercial lending | Commercial real estate (“CRE”)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	837	0	837
Commercial lending | Commercial real estate (“CRE”) | Principal
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	0	0	0
Commercial lending | Commercial real estate (“CRE”) | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	837	0	837
Commercial lending | Commercial real estate (“CRE”) | Other (2)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	0	0	0
Consumer lending
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	219	1,940	219	1,940
Consumer lending | Principal
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	1,529	0	1,529
Consumer lending | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	0	0	0
Consumer lending | Other (2)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	219	411	219	411
Consumer lending | Real estate loan | Single-family residential
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	219	404	219	404
Consumer lending | Real estate loan | Single-family residential | Principal
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	65	0	65
Consumer lending | Real estate loan | Single-family residential | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	0	0	0
Consumer lending | Real estate loan | Single-family residential | Other (2)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	219	339	219	339
Consumer lending | HELOCs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	1,536	0	1,536
Consumer lending | HELOCs | Principal
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	1,464	0	1,464
Consumer lending | HELOCs | Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	0	0	0	0
Consumer lending | HELOCs | Other (2)
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post- Modification Outstanding Recorded Investment	$ 0	$ 72	$ 0	$ 72