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Loans (Analysis of Impaired Loans) (Details) - Loans, Excluding Purchased Credit Impaired Loans [Member] - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | $ 8,158,383 |  | $ 8,176,782
Recorded Investment of Loans Individually Measured for Specific Impairment | 71,949 |  | 69,205
Recorded Investment | 48,824 |  | 56,357
Unpaid Principal Balance | 52,674 |  | 64,735
Related Allowance | 5,857 |  | 2,360
Average Recorded Investment Impaired Loans | 70,577 | $ 24,394 |
Interest Recognized on Impaired Loans | 239 | 49 |
Secured Loans [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 3,221,659 |  | 3,195,649
Recorded Investment of Loans Individually Measured for Specific Impairment | 44,600 |  | 40,012
Recorded Investment | 13,836 |  | 3,808
Unpaid Principal Balance | 18,931 |  | 3,937
Related Allowance | 5,657 |  | 1,867
Average Recorded Investment Impaired Loans | 42,306 | 8,303 |
Interest Recognized on Impaired Loans | 12 | 19 |
Unsecured Loans [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 120,056 |  | 124,150
Recorded Investment of Loans Individually Measured for Specific Impairment | 23 |  | 25
Recorded Investment | 23 |  | 25
Unpaid Principal Balance | 23 |  | 24
Related Allowance | 2 |  | 3
Average Recorded Investment Impaired Loans | 24 | 0 |
Interest Recognized on Impaired Loans | 0 | 0 |
One-to-Four Family Residential [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 179,700 |  | 185,659
Recorded Investment of Loans Individually Measured for Specific Impairment | 868 |  | 895
Recorded Investment | 428 |  | 867
Unpaid Principal Balance | 715 |  | 1,408
Related Allowance | 22 |  | 103
Average Recorded Investment Impaired Loans | 881 | 521 |
Interest Recognized on Impaired Loans | 7 | 2 |
Commercial Land [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 286,613 |  | 293,694
Recorded Investment of Loans Individually Measured for Specific Impairment | 2,851 |  | 2,287
Recorded Investment | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0
Related Allowance | 0 |  | 0
Average Recorded Investment Impaired Loans | 2,569 | 1,504 |
Interest Recognized on Impaired Loans | 0 | 0 |
Income Property Multifamily [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 1,870,614 |  | 1,901,313
Recorded Investment of Loans Individually Measured for Specific Impairment | 3,560 |  | 5,023
Recorded Investment | 0 |  | 2,768
Unpaid Principal Balance | 0 |  | 3,328
Related Allowance | 0 |  | 185
Average Recorded Investment Impaired Loans | 4,292 | 4,059 |
Interest Recognized on Impaired Loans | 31 | 1 |
Owner Occupied [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 1,582,385 |  | 1,591,298
Recorded Investment of Loans Individually Measured for Specific Impairment | 8,556 |  | 8,688
Recorded Investment | 3,399 |  | 77
Unpaid Principal Balance | 4,821 |  | 80
Related Allowance | 5 |  | 3
Average Recorded Investment Impaired Loans | 8,622 | 4,462 |
Interest Recognized on Impaired Loans | 84 | 0 |
Land And Acquisition [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 6,540 |  | 9,907
Recorded Investment of Loans Individually Measured for Specific Impairment | 0 |  | 0
Recorded Investment | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0
Related Allowance | 0 |  | 0
Average Recorded Investment Impaired Loans | 0 | 7 |
Interest Recognized on Impaired Loans | 0 | 0 |
Residential Construction [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 199,868 |  | 188,481
Recorded Investment of Loans Individually Measured for Specific Impairment | 1,210 |  | 1,210
Recorded Investment | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0
Related Allowance | 0 |  | 0
Average Recorded Investment Impaired Loans | 1,210 | 168 |
Interest Recognized on Impaired Loans | 0 | 0 |
Income Property Multifamily Construction [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 306,137 |  | 293,028
Recorded Investment of Loans Individually Measured for Specific Impairment | 0 |  | 0
Recorded Investment | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0
Related Allowance | 0 |  | 0
Owner Occupied Construction [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 68,966 |  | 68,393
Recorded Investment of Loans Individually Measured for Specific Impairment | 4,050 |  | 4,050
Recorded Investment | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0
Related Allowance | 0 |  | 0
Average Recorded Investment Impaired Loans | 4,050 | 0 |
Interest Recognized on Impaired Loans | 51 | 0 |
Consumer Portfolio Segment [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 315,845 |  | 325,210
Recorded Investment of Loans Individually Measured for Specific Impairment | 6,231 |  | 7,015
Recorded Investment | 5,439 |  | 5,303
Unpaid Principal Balance | 5,707 |  | 5,568
Related Allowance | 171 |  | 199
Average Recorded Investment Impaired Loans | 6,623 | 5,370 |
Interest Recognized on Impaired Loans | 54 | $ 27 |
Impaired Loans With Recorded Allowance [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 23,125 |  | 12,848
Unpaid Principal Balance | 30,197 |  | 14,345
Impaired Loans Without Recorded Allowance [Member] | Secured Loans [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 30,764 |  | 36,204
Unpaid Principal Balance | 33,785 |  | 42,314
Impaired Loans Without Recorded Allowance [Member] | Unsecured Loans [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0
Impaired Loans Without Recorded Allowance [Member] | One-to-Four Family Residential [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 440 |  | 28
Unpaid Principal Balance | 1,017 |  | 337
Impaired Loans Without Recorded Allowance [Member] | Commercial Land [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 2,851 |  | 2,287
Unpaid Principal Balance | 2,860 |  | 2,282
Impaired Loans Without Recorded Allowance [Member] | Income Property Multifamily [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 3,560 |  | 2,255
Unpaid Principal Balance | 3,623 |  | 2,601
Impaired Loans Without Recorded Allowance [Member] | Owner Occupied [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 5,157 |  | 8,611
Unpaid Principal Balance | 5,269 |  | 10,077
Impaired Loans Without Recorded Allowance [Member] | Land And Acquisition [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0
Impaired Loans Without Recorded Allowance [Member] | Residential Construction [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 1,210 |  | 1,210
Unpaid Principal Balance | 1,210 |  | 1,210
Impaired Loans Without Recorded Allowance [Member] | Income Property Multifamily Construction [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0
Impaired Loans Without Recorded Allowance [Member] | Owner Occupied Construction [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 4,050 |  | 4,050
Unpaid Principal Balance | 4,050 |  | 4,050
Impaired Loans Without Recorded Allowance [Member] | Consumer Portfolio Segment [Member] |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |
Recorded Investment | 792 |  | 1,712
Unpaid Principal Balance | $ 860 |  | $ 1,864

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