Loans (Analysis of the Aged Loan Portfolio) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	$ 78,464	$ 66,189
Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	8,100,317	8,163,583
Past Due Loans	51,551	16,215
Nonaccrual Loans	78,464	66,189
Loans Receivable, Net	8,230,332	8,245,987
Secured Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	57,504	45,410
Secured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	3,189,473	3,185,321
Past Due Loans	19,282	4,930
Nonaccrual Loans	57,504	45,410
Loans Receivable, Net	3,266,259	3,235,661
Unsecured Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	115	50
Unsecured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	119,863	123,524
Past Due Loans	101	601
Nonaccrual Loans	115	50
Loans Receivable, Net	120,079	124,175
One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	1,054	785
One-to-Four Family Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	179,174	184,256
Past Due Loans	340	1,513
Nonaccrual Loans	1,054	785
Loans Receivable, Net	180,568	186,554
Commercial Land [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	3,192	2,628
Commercial Land [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	283,973	292,680
Past Due Loans	2,299	673
Nonaccrual Loans	3,192	2,628
Loans Receivable, Net	289,464	295,981
Income Property Multifamily [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	3,980	4,284
Income Property Multifamily [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	1,867,450	1,898,655
Past Due Loans	2,744	3,397
Nonaccrual Loans	3,980	4,284
Loans Receivable, Net	1,874,174	1,906,336
Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	7,367	7,029
Owner Occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	1,570,051	1,590,004
Past Due Loans	13,523	2,953
Nonaccrual Loans	7,367	7,029
Loans Receivable, Net	1,590,941	1,599,986
Land And Acquisition [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	0	25
Land And Acquisition [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	5,937	9,882
Past Due Loans	603	0
Nonaccrual Loans	0	25
Loans Receivable, Net	6,540	9,907
Residential Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	1,210	1,829
Residential Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	199,756	187,862
Past Due Loans	112	0
Nonaccrual Loans	1,210	1,829
Loans Receivable, Net	201,078	189,691
Income Property Multifamily Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	295,067	293,028
Past Due Loans	11,070	0
Nonaccrual Loans	0	0
Loans Receivable, Net	306,137	293,028
Owner Occupied Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	73,016	72,443
Past Due Loans	0	0
Nonaccrual Loans	0	0
Loans Receivable, Net	73,016	72,443
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual Loans	4,042	4,149
Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current Loans	316,557	325,928
Past Due Loans	1,477	2,148
Nonaccrual Loans	4,042	4,149
Loans Receivable, Net	322,076	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	7,043	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	2,872	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	51	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	0	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	815	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	2,772	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	285	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	0	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	248	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	44,508	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	16,410	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	50	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	340	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	2,299	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	1,929	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	10,751	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	318	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	112	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	11,070	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	1,229	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