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Loans Loans, analysis of purchased credit impaired loans (Details) - USD ($) $ in Thousands | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | --- | --- | ---
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Allowance | $ 83,369 | $ 75,646 | $ 70,043 | $ 68,172
Loans and Leases Receivable, Net Amount | 8,308,142 | 8,283,011 |  |
Real estate: One-to-four family residential [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Allowance | 593 | 701 | 599 | 916
Consumer [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Allowance | 5,301 | 5,163 | $ 3,534 | $ 3,531
Purchased Credit Impaired Loans [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Carrying Amount | 96,285 | 120,758 |  |
Valuation discount resulting from acquisition accounting | 6,525 | 8,088 |  |
Loans and Leases Receivable, Allowance | 3,611 | 6,907 |  |
Loans and Leases Receivable, Net Amount | 86,149 | 105,763 |  |
Purchased Credit Impaired Loans [Member] | Commercial Portfolio Segment [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Carrying Amount | 9,672 | 13,753 |  |
Purchased Credit Impaired Loans [Member] | Real estate: One-to-four family residential [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Carrying Amount | 9,848 | 14,610 |  |
Purchased Credit Impaired Loans [Member] | Commercial and Multifamily Residential [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Carrying Amount | 66,340 | 79,211 |  |
Purchased Credit Impaired Loans [Member] | Real Estate Portfolio Segment [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Carrying Amount | 76,188 | 93,821 |  |
Purchased Credit Impaired Loans [Member] | One-to-Four Family Residential Construction [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Carrying Amount | 153 | 177 |  |
Purchased Credit Impaired Loans [Member] | Commercial and Multifamily Residential Construction [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Carrying Amount | 507 | 595 |  |
Purchased Credit Impaired Loans [Member] | Real Estate Construction Portfolio Segment [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Carrying Amount | 660 | 772 |  |
Purchased Credit Impaired Loans [Member] | Consumer [Member] |  |  |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |  |  |
Loans and Leases Receivable, Gross, Carrying Amount | $ 9,765 | $ 12,412 |  |

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- Definition Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.7(d)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b)(1)(ii) -URI http://asc.fasb.org/extlink&oid=82894903&loc=d3e15032-111544 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB Topic 6.L.1) -URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707 + Details
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