Loans Receivable and Allowance for Credit Losses (Non-PCI TDR Modifications) (Details) - Non-PCI impaired loans - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	$ 12,081	$ 43,651	$ 65,762
Principal
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	6,891	19,164	57,729
Principal and Interest
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	8,003	0
Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	752	0	6,722
Interest Deferments
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	237
Other
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	4,438	16,484	1,074
Commercial Lending
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	10,272	43,496	64,112
Commercial Lending | Principal
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	5,472	19,164	57,132
Commercial Lending | Principal and Interest
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	7,848	0
Commercial Lending | Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	752	0	5,876
Commercial Lending | Interest Deferments
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	30
Commercial Lending | Other
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	4,048	16,484	1,074
Commercial Lending | C&I
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	9,520	37,900	40,405
Commercial Lending | C&I | Principal
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	5,472	13,568	34,499
Commercial Lending | C&I | Principal and Interest
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	7,848	0
Commercial Lending | C&I | Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	5,876
Commercial Lending | C&I | Interest Deferments
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	30
Commercial Lending | C&I | Other
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	4,048	16,484	0
Commercial Lending | CRE
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	752	2,627	18,824
Commercial Lending | CRE | Principal
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	2,627	17,750
Commercial Lending | CRE | Principal and Interest
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	0
Commercial Lending | CRE | Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	752	0	0
Commercial Lending | CRE | Interest Deferments
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	0
Commercial Lending | CRE | Other
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	1,074
Commercial Lending | Residential loan | Multifamily
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment		2,969
Commercial Lending | Residential loan | Multifamily | Principal
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment		2,969
Commercial Lending | Residential loan | Multifamily | Principal and Interest
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment		0
Commercial Lending | Residential loan | Multifamily | Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment		0
Commercial Lending | Residential loan | Multifamily | Interest Deferments
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment		0
Commercial Lending | Residential loan | Multifamily | Other
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment		0
Commercial Lending | Construction and land
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment			4,883
Commercial Lending | Construction and land | Principal
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment			4,883
Commercial Lending | Construction and land | Principal and Interest
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment			0
Commercial Lending | Construction and land | Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment			0
Commercial Lending | Construction and land | Interest Deferments
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment			0
Commercial Lending | Construction and land | Other
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment			0
Consumer Lending
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	1,809	155	1,650
Consumer Lending | Principal
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	1,419	0	597
Consumer Lending | Principal and Interest
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	155	0
Consumer Lending | Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	846
Consumer Lending | Interest Deferments
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	207
Consumer Lending | Other
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	390	0	0
Consumer Lending | Residential loan | Single-family
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	391		1,268
Consumer Lending | Residential loan | Single-family | Principal
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	66		264
Consumer Lending | Residential loan | Single-family | Principal and Interest
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0		0
Consumer Lending | Residential loan | Single-family | Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0		797
Consumer Lending | Residential loan | Single-family | Interest Deferments
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0		207
Consumer Lending | Residential loan | Single-family | Other
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	325		0
Consumer Lending | HELOCs
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	1,418	155	382
Consumer Lending | HELOCs | Principal
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	1,353	0	333
Consumer Lending | HELOCs | Principal and Interest
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	155	0
Consumer Lending | HELOCs | Interest Rate Reduction
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	49
Consumer Lending | HELOCs | Interest Deferments
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	0	0	0
Consumer Lending | HELOCs | Other
Financing Receivable, Modifications [Line Items]
Post-Modification Outstanding Recorded Investment	$ 65	$ 0	$ 0