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Loans (Analysis of Loan Portfolio by Major Types of Loans) (Details) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018 | Mar. 31, 2018 | Dec. 31, 2017
--- | --- | --- | --- | ---
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Less: unearned income on loans | $ (38,681) | $ (42,194) |  |
Recorded Investment | 8,520,798 | 8,391,511 |  |
Allowance for loan losses | (83,274) | (83,369) | $ (79,827) | $ (75,646)
Loans, net | 8,437,524 | 8,308,142 |  |
Loans held for sale | 4,017 | 3,849 |  |
Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Less: unearned income on loans | (38,681) | (42,194) |  |
Recorded Investment | 8,432,541 | 8,301,751 |  |
Allowance for loan losses | (80,029) | (79,758) |  |
Loans, net | 8,352,512 | 8,221,993 |  |
Loans held for sale | 4,017 | 3,849 |  |
Loans and Leases Receivable, Gross | 8,432,541 | 8,301,751 |  |
Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Less: unearned income on loans | 0 | 0 |  |
Recorded Investment | 88,257 | 89,760 |  |
Allowance for loan losses | (3,245) | (3,611) |  |
Loans, net | 85,012 | 86,149 |  |
Loans held for sale | 0 | 0 |  |
Loans and Leases Receivable, Gross | 94,418 | 96,285 |  |
Acquisition Accounting Valuation Discount on Covered Loans | 6,161 | 6,525 |  |
Commercial Portfolio Segment [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable, Gross, Commercial and Industrial | 3,519,386 | 3,447,662 |  |
Commercial Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable, Gross, Commercial and Industrial | 3,509,472 | 3,438,422 |  |
Commercial Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable, Gross, Commercial and Industrial | 9,914 | 9,240 |  |
Loans and Leases Receivable, Gross | 10,270 | 9,672 |  |
One-to-Four Family Residential [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Consumer, Mortgage | 290,167 | 246,384 |  |
Loans and Leases Receivable, Gross, Consumer, Construction | 208,047 | 217,943 |  |
Allowance for loan losses | (616) | (593) | (558) | (701)
One-to-Four Family Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Consumer, Mortgage | 282,673 | 238,367 |  |
Loans and Leases Receivable, Gross, Consumer, Construction | 207,900 | 217,790 |  |
Loans and Leases Receivable, Gross | 282,330 | 236,026 |  |
One-to-Four Family Residential [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Consumer, Mortgage | 7,494 | 8,017 |  |
Loans and Leases Receivable, Gross, Consumer, Construction | 147 | 153 |  |
Loans and Leases Receivable, Gross | 9,258 | 9,848 |  |
Commercial and Multifamily Residential [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable, Gross, Commercial, Mortgage | 3,979,494 | 3,908,937 |  |
Loans Receivable, Gross, Commercial, Construction | 240,977 | 284,928 |  |
Commercial and Multifamily Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable, Gross, Commercial, Mortgage | 3,917,833 | 3,846,027 |  |
Loans Receivable, Gross, Commercial, Construction | 240,458 | 284,394 |  |
Commercial and Multifamily Residential [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable, Gross, Commercial, Mortgage | 61,661 | 62,910 |  |
Loans Receivable, Gross, Commercial, Construction | 519 | 534 |  |
Loans and Leases Receivable, Gross | 64,958 | 66,340 |  |
Real Estate Portfolio Segment [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable Real Estate Mortgage | 4,269,661 | 4,155,321 |  |
Real Estate Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable Real Estate Mortgage | 4,200,506 | 4,084,394 |  |
Real Estate Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable Real Estate Mortgage | 69,155 | 70,927 |  |
Loans and Leases Receivable, Gross | 74,216 | 76,188 |  |
Real Estate Construction Portfolio Segment [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable Real Estate Construction | 449,024 | 502,871 |  |
Real Estate Construction Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable Real Estate Construction | 448,358 | 502,184 |  |
Real Estate Construction Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans Receivable Real Estate Construction | 666 | 687 |  |
Loans and Leases Receivable, Gross | 638 | 660 |  |
Consumer Portfolio Segment [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Consumer | 321,408 | 327,851 |  |
Allowance for loan losses | (5,545) | (5,301) | $ (5,216) | $ (5,163)
Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Consumer | 312,886 | 318,945 |  |
Loans and Leases Receivable, Gross | 312,325 | 318,215 |  |
Consumer Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Consumer | 8,522 | 8,906 |  |
Loans and Leases Receivable, Gross | 9,294 | 9,765 |  |
One-to-Four Family Residential Construction [Domain] | Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans and Leases Receivable, Gross | 147 | 153 |  |
Commercial and Multifamily Residential Construction [Domain] | Purchased Credit Impaired Loans [Member] |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |
Loans and Leases Receivable, Gross | $ 491 | $ 507 |  |

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