Loans (Analysis of the Aged Loan Portfolio) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	$ 60,332	$ 66,189
Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	8,332,359	8,163,583
Past Due Loans	25,690	16,215
Nonaccrual Loans	60,332	66,189
Loans Receivable, Net	8,418,381	8,245,987
Secured Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	45,753	45,410
Secured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	3,365,159	3,185,321
Past Due Loans	9,399	4,930
Nonaccrual Loans	45,753	45,410
Loans Receivable, Net	3,420,311	3,235,661
Unsecured Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	0	50
Unsecured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	117,801	123,524
Past Due Loans	1,118	601
Nonaccrual Loans	0	50
Loans Receivable, Net	118,919	124,175
One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	501	785
One-to-Four Family Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	229,685	184,256
Past Due Loans	1,125	1,513
Nonaccrual Loans	501	785
Loans Receivable, Net	231,311	186,554
Commercial Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	2,461	2,628
Commercial Land [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	278,777	292,680
Past Due Loans	0	673
Nonaccrual Loans	2,461	2,628
Loans Receivable, Net	281,238	295,981
Income Property Multifamily [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	1,873	4,284
Income Property Multifamily [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	1,880,405	1,898,655
Past Due Loans	5,412	3,397
Nonaccrual Loans	1,873	4,284
Loans Receivable, Net	1,887,690	1,906,336
Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	6,678	7,029
Owner Occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	1,588,662	1,590,004
Past Due Loans	1,929	2,953
Nonaccrual Loans	6,678	7,029
Loans Receivable, Net	1,597,269	1,599,986
Land And Acquisition [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	318	25
Land And Acquisition [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	5,320	9,882
Past Due Loans	325	0
Nonaccrual Loans	318	25
Loans Receivable, Net	5,963	9,907
Residential Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	0	1,829
Residential Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	200,484	187,862
Past Due Loans	4,144	0
Nonaccrual Loans	0	1,829
Loans Receivable, Net	204,628	189,691
Income Property Multifamily Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	253,470	293,028
Past Due Loans	166	0
Nonaccrual Loans	0	0
Loans Receivable, Net	253,636	293,028
Owner Occupied Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	90,511	72,443
Past Due Loans	0	0
Nonaccrual Loans	0	0
Loans Receivable, Net	90,511	72,443
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	2,748	4,149
Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	322,085	325,928
Past Due Loans	2,072	2,148
Nonaccrual Loans	2,748	4,149
Loans Receivable, Net	326,905	332,225
Financing Receivables, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	5,565	5,444
Financing Receivables, 60 to 89 Days Past Due [Member] | Secured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	2,258	2,400
Financing Receivables, 60 to 89 Days Past Due [Member] | Unsecured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	501
Financing Receivables, 60 to 89 Days Past Due [Member] | One-to-Four Family Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	784	402
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Land [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Income Property Multifamily [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	2,073	971
Financing Receivables, 60 to 89 Days Past Due [Member] | Owner Occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	468
Financing Receivables, 60 to 89 Days Past Due [Member] | Land And Acquisition [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Income Property Multifamily Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	166	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Owner Occupied Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	284	702
Financing Receivables, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	20,125	10,190
Financing Receivables, 30 to 59 Days Past Due [Member] | Secured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	7,141	2,530
Financing Receivables, 30 to 59 Days Past Due [Member] | Unsecured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	1,118	100
Financing Receivables, 30 to 59 Days Past Due [Member] | One-to-Four Family Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	341	1,111
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Land [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	92
Financing Receivables, 30 to 59 Days Past Due [Member] | Income Property Multifamily [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	3,339	2,426
Financing Receivables, 30 to 59 Days Past Due [Member] | Owner Occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	1,929	2,485
Financing Receivables, 30 to 59 Days Past Due [Member] | Land And Acquisition [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	325	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	4,144	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Income Property Multifamily Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Owner Occupied Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	1,788	1,446
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	581
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Secured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Unsecured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | One-to-Four Family Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Land [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	581
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Income Property Multifamily [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Owner Occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Land And Acquisition [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Income Property Multifamily Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Owner Occupied Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	$ 0	$ 0