Loans (Analysis of the Aged Loan Portfolio) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	$ 37,021	$ 54,842
Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	8,612,450	8,218,651
Past Due Loans	25,107	28,258
Nonaccrual Loans	37,021	54,842
Total Loans	8,674,578	8,301,751
Secured Loans [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	24,408	35,504
Secured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	3,525,753	3,267,709
Past Due Loans	5,822	9,488
Nonaccrual Loans	24,408	35,504
Total Loans	3,555,983	3,312,701
Unsecured Loans [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	0	9
Unsecured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	138,947	111,868
Past Due Loans	426	240
Nonaccrual Loans	0	9
Total Loans	139,373	112,117
One-to-Four Family Residential [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	574	1,158
One-to-Four Family Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	269,593	233,941
Past Due Loans	2,866	927
Nonaccrual Loans	574	1,158
Total Loans	273,033	236,026
Commercial Land [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	2,562	2,261
Commercial Land [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	292,594	283,416
Past Due Loans	140	0
Nonaccrual Loans	2,562	2,261
Total Loans	295,296	285,677
Income Property Multifamily [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	997	2,721
Income Property Multifamily [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	1,955,634	1,910,505
Past Due Loans	5,304	7,250
Nonaccrual Loans	997	2,721
Total Loans	1,961,935	1,920,476
Owner Occupied [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	6,524	9,922
Owner Occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	1,689,919	1,606,085
Past Due Loans	1,865	1,744
Nonaccrual Loans	6,524	9,922
Total Loans	1,698,308	1,617,751
Land And Acquisition [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	0	318
Land And Acquisition [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	1,614	4,099
Past Due Loans	0	0
Nonaccrual Loans	0	318
Total Loans	1,614	4,417
Residential Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	192,563	212,303
Past Due Loans	0	93
Nonaccrual Loans	0	0
Total Loans	192,563	212,396
Income Property Multifamily Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	151,362	194,912
Past Due Loans	6,038	0
Nonaccrual Loans	0	0
Total Loans	157,400	194,912
Owner Occupied Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	100,610	79,805
Past Due Loans	1,636	7,258
Nonaccrual Loans	0	0
Total Loans	102,246	87,063
Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	1,956	2,949
Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	293,861	314,008
Past Due Loans	1,010	1,258
Nonaccrual Loans	1,956	2,949
Total Loans	296,827	318,215
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	4,369	6,299
Financial Asset, 60 to 89 Days Past Due [Member] | Secured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	262	3,624
Financial Asset, 60 to 89 Days Past Due [Member] | Unsecured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	2	0
Financial Asset, 60 to 89 Days Past Due [Member] | One-to-Four Family Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	437	233
Financial Asset, 60 to 89 Days Past Due [Member] | Commercial Land [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Income Property Multifamily [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	3,266	2,241
Financial Asset, 60 to 89 Days Past Due [Member] | Owner Occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	138	0
Financial Asset, 60 to 89 Days Past Due [Member] | Land And Acquisition [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Residential Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Income Property Multifamily Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Owner Occupied Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	264	201
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	20,738	21,959
Financial Asset, 30 to 59 Days Past Due [Member] | Secured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	5,560	5,864
Financial Asset, 30 to 59 Days Past Due [Member] | Unsecured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	424	240
Financial Asset, 30 to 59 Days Past Due [Member] | One-to-Four Family Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	2,429	694
Financial Asset, 30 to 59 Days Past Due [Member] | Commercial Land [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	140	0
Financial Asset, 30 to 59 Days Past Due [Member] | Income Property Multifamily [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	2,038	5,009
Financial Asset, 30 to 59 Days Past Due [Member] | Owner Occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	1,727	1,744
Financial Asset, 30 to 59 Days Past Due [Member] | Land And Acquisition [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Residential Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	93
Financial Asset, 30 to 59 Days Past Due [Member] | Income Property Multifamily Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	6,038	0
Financial Asset, 30 to 59 Days Past Due [Member] | Owner Occupied Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	1,636	7,258
Financial Asset, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	746	1,057
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Secured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Unsecured Loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | One-to-Four Family Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Commercial Land [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Income Property Multifamily [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Owner Occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Land And Acquisition [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Residential Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Income Property Multifamily Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Owner Occupied Construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Past Due Loans	$ 0	$ 0