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Loans (Analysis of Impaired Loans) (Details) - Loans, Excluding Purchased Credit Impaired Loans [Member] - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2017
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | $ 8,279,959 |  | $ 8,279,959 |  | $ 8,176,782
Recorded Investment of Loans Individually Measured for Specific Impairment | 72,366 |  | 72,366 |  | 69,205
Recorded Investment | 60,688 |  | 60,688 |  | 56,357
Unpaid Principal Balance | 74,464 |  | 74,464 |  | 64,735
Related Allowance | 256 |  | 256 |  | 2,360
Average Recorded Investment Impaired Loans | 72,157 | $ 31,500 | 71,173 | $ 29,486 |
Interest Recognized on Impaired Loans | 339 | 301 | 566 | 346 |
Secured Loans [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 3,360,586 |  | 3,360,586 |  | 3,195,649
Recorded Investment of Loans Individually Measured for Specific Impairment | 46,833 |  | 46,833 |  | 40,012
Recorded Investment | 2,731 |  | 2,731 |  | 3,808
Unpaid Principal Balance | 3,120 |  | 3,120 |  | 3,937
Related Allowance | 67 |  | 67 |  | 1,867
Average Recorded Investment Impaired Loans | 45,716 | 15,590 | 43,815 | 13,332 |
Interest Recognized on Impaired Loans | 85 | 50 | 97 | 69 |
Unsecured Loans [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 115,468 |  | 115,468 |  | 124,150
Recorded Investment of Loans Individually Measured for Specific Impairment | 866 |  | 866 |  | 25
Recorded Investment | 0 |  | 0 |  | 25
Unpaid Principal Balance | 0 |  | 0 |  | 24
Related Allowance | 0 |  | 0 |  | 3
Average Recorded Investment Impaired Loans | 444 | 0 | 304 | 0 |
Interest Recognized on Impaired Loans | 1 | 0 | 1 | 0 |
One-to-Four Family Residential [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 178,121 |  | 178,121 |  | 185,659
Recorded Investment of Loans Individually Measured for Specific Impairment | 693 |  | 693 |  | 895
Recorded Investment | 346 |  | 346 |  | 867
Unpaid Principal Balance | 742 |  | 742 |  | 1,408
Related Allowance | 8 |  | 8 |  | 103
Average Recorded Investment Impaired Loans | 780 | 648 | 818 | 608 |
Interest Recognized on Impaired Loans | 12 | 21 | 18 | 22 |
Commercial Land [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 279,408 |  | 279,408 |  | 293,694
Recorded Investment of Loans Individually Measured for Specific Impairment | 2,262 |  | 2,262 |  | 2,287
Recorded Investment | 0 |  | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0 |  | 0
Related Allowance | 0 |  | 0 |  | 0
Average Recorded Investment Impaired Loans | 2,557 | 2,549 | 2,467 | 1,936 |
Interest Recognized on Impaired Loans | 0 | 0 | 0 | 0 |
Income Property Multifamily [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 1,849,318 |  | 1,849,318 |  | 1,901,313
Recorded Investment of Loans Individually Measured for Specific Impairment | 2,132 |  | 2,132 |  | 5,023
Recorded Investment | 0 |  | 0 |  | 2,768
Unpaid Principal Balance | 0 |  | 0 |  | 3,328
Related Allowance | 0 |  | 0 |  | 185
Average Recorded Investment Impaired Loans | 2,846 | 3,676 | 3,572 | 3,925 |
Interest Recognized on Impaired Loans | 32 | 7 | 62 | 6 |
Owner Occupied [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 1,594,762 |  | 1,594,762 |  | 1,591,298
Recorded Investment of Loans Individually Measured for Specific Impairment | 8,980 |  | 8,980 |  | 8,688
Recorded Investment | 3,299 |  | 3,299 |  | 77
Unpaid Principal Balance | 4,717 |  | 4,717 |  | 80
Related Allowance | 86 |  | 86 |  | 3
Average Recorded Investment Impaired Loans | 8,768 | 3,453 | 8,741 | 4,107 |
Interest Recognized on Impaired Loans | 124 | 192 | 209 | 192 |
Land And Acquisition [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 6,570 |  | 6,570 |  | 9,907
Recorded Investment of Loans Individually Measured for Specific Impairment | 0 |  | 0 |  | 0
Recorded Investment | 0 |  | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0 |  | 0
Related Allowance | 0 |  | 0 |  | 0
Average Recorded Investment Impaired Loans | 0 | 0 | 0 | 5 |
Interest Recognized on Impaired Loans | 0 | 0 | 0 | 0 |
Residential Construction [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 198,673 |  | 198,673 |  | 188,481
Recorded Investment of Loans Individually Measured for Specific Impairment | 0 |  | 0 |  | 1,210
Recorded Investment | 0 |  | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0 |  | 0
Related Allowance | 0 |  | 0 |  | 0
Average Recorded Investment Impaired Loans | 605 | 0 | 807 | 112 |
Interest Recognized on Impaired Loans | 0 | 0 | 0 | 0 |
Income Property Multifamily Construction [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 302,801 |  | 302,801 |  | 293,028
Recorded Investment of Loans Individually Measured for Specific Impairment | 0 |  | 0 |  | 0
Recorded Investment | 0 |  | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0 |  | 0
Related Allowance | 0 |  | 0 |  | 0
Owner Occupied Construction [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 75,644 |  | 75,644 |  | 68,393
Recorded Investment of Loans Individually Measured for Specific Impairment | 4,050 |  | 4,050 |  | 4,050
Recorded Investment | 0 |  | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0 |  | 0
Related Allowance | 0 |  | 0 |  | 0
Average Recorded Investment Impaired Loans | 4,050 | 0 | 4,050 | 0 |
Interest Recognized on Impaired Loans | 51 | 0 | 102 | 0 |
Consumer Portfolio Segment [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment of Loans Collectively Measured for Contingency Provision | 318,608 |  | 318,608 |  | 325,210
Recorded Investment of Loans Individually Measured for Specific Impairment | 6,550 |  | 6,550 |  | 7,015
Recorded Investment | 5,302 |  | 5,302 |  | 5,303
Unpaid Principal Balance | 5,590 |  | 5,590 |  | 5,568
Related Allowance | 95 |  | 95 |  | 199
Average Recorded Investment Impaired Loans | 6,391 | 5,584 | 6,599 | 5,461 |
Interest Recognized on Impaired Loans | 34 | $ 31 | 77 | $ 57 |
Impaired Loans With Recorded Allowance [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 11,678 |  | 11,678 |  | 12,848
Unpaid Principal Balance | 14,169 |  | 14,169 |  | 14,345
Impaired Loans Without Recorded Allowance [Member] | Secured Loans [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 44,102 |  | 44,102 |  | 36,204
Unpaid Principal Balance | 53,050 |  | 53,050 |  | 42,314
Impaired Loans Without Recorded Allowance [Member] | Unsecured Loans [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 866 |  | 866 |  | 0
Unpaid Principal Balance | 4,906 |  | 4,906 |  | 0
Impaired Loans Without Recorded Allowance [Member] | One-to-Four Family Residential [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 347 |  | 347 |  | 28
Unpaid Principal Balance | 809 |  | 809 |  | 337
Impaired Loans Without Recorded Allowance [Member] | Commercial Land [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 2,262 |  | 2,262 |  | 2,287
Unpaid Principal Balance | 2,277 |  | 2,277 |  | 2,282
Impaired Loans Without Recorded Allowance [Member] | Income Property Multifamily [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 2,132 |  | 2,132 |  | 2,255
Unpaid Principal Balance | 2,195 |  | 2,195 |  | 2,601
Impaired Loans Without Recorded Allowance [Member] | Owner Occupied [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 5,681 |  | 5,681 |  | 8,611
Unpaid Principal Balance | 5,858 |  | 5,858 |  | 10,077
Impaired Loans Without Recorded Allowance [Member] | Land And Acquisition [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 0 |  | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0 |  | 0
Impaired Loans Without Recorded Allowance [Member] | Residential Construction [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 0 |  | 0 |  | 1,210
Unpaid Principal Balance | 0 |  | 0 |  | 1,210
Impaired Loans Without Recorded Allowance [Member] | Income Property Multifamily Construction [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 0 |  | 0 |  | 0
Unpaid Principal Balance | 0 |  | 0 |  | 0
Impaired Loans Without Recorded Allowance [Member] | Owner Occupied Construction [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 4,050 |  | 4,050 |  | 4,050
Unpaid Principal Balance | 4,050 |  | 4,050 |  | 4,050
Impaired Loans Without Recorded Allowance [Member] | Consumer Portfolio Segment [Member] |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |
Recorded Investment | 1,248 |  | 1,248 |  | 1,712
Unpaid Principal Balance | $ 1,319 |  | $ 1,319 |  | $ 1,864

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