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Loans (Analysis of Loan Portfolio by Major Types of Loans) (Details) - USD ($) $ in Thousands | Sep. 30, 2017 | Jun. 30, 2017 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Dec. 31, 2015
--- | --- | --- | --- | --- | --- | ---
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Less: unearned income on loans | $ (29,229) |  | $ (33,718) |  |  |
Recorded Investment | 6,512,006 |  | 6,213,423 |  |  |
Allowance for loan losses | (71,616) | $ (72,984) | (70,043) | $ (70,264) | $ (69,304) | $ (68,172)
Loans, net | 6,440,390 |  | 6,143,380 |  |  |
Loans held for sale | 7,802 |  | 5,846 |  |  |
Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Less: unearned income on loans | (29,229) |  | (33,718) |  |  |
Recorded Investment | 6,391,529 |  | 6,067,763 |  |  |
Allowance for loan losses | (64,272) |  | (59,528) |  |  |
Loans, net | 6,327,257 |  | 6,008,235 |  |  |
Loans held for sale | 7,802 |  | 5,846 |  |  |
Loans and Leases Receivable, Gross | 6,391,529 |  | 6,067,763 |  |  |
Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Less: unearned income on loans | 0 |  | 0 |  |  |
Recorded Investment | 120,477 |  | 145,660 |  |  |
Allowance for loan losses | (7,344) |  | (10,515) |  |  |
Loans, net | 113,133 |  | 135,145 |  |  |
Loans held for sale | 0 |  | 0 |  |  |
Loans and Leases Receivable, Gross | 129,150 |  | 157,251 |  |  |
Acquisition Accounting Valuation Discount on Covered Loans | 8,673 |  | 11,591 |  |  |
Commercial and Multifamily Residential Construction [Domain] | Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans and Leases Receivable, Gross | 1,059 |  | 1,726 |  |  |
One-to-Four Family Residential [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans and Leases Receivable, Gross, Consumer, Mortgage | 190,812 |  | 188,193 |  |  |
Loans and Leases Receivable, Gross, Consumer, Construction | 145,796 |  | 122,719 |  |  |
Allowance for loan losses | (671) | (628) | (599) | (977) | (675) | (916)
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 | 176,487 |  | 170,331 |  |  |
Loans and Leases Receivable, Gross, Consumer, Construction | 145,419 |  | 121,887 |  |  |
Loans and Leases Receivable, Gross | 174,490 |  | 167,932 |  |  |
One-to-Four Family Residential [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans and Leases Receivable, Gross, Consumer, Mortgage | 14,325 |  | 17,862 |  |  |
Loans and Leases Receivable, Gross, Consumer, Construction | 377 |  | 832 |  |  |
Loans and Leases Receivable, Gross | 16,698 |  | 20,643 |  |  |
Commercial and Multifamily Residential [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable, Gross, Commercial, Mortgage | 2,905,130 |  | 2,809,061 |  |  |
Loans Receivable, Gross, Commercial, Construction | 214,897 |  | 210,683 |  |  |
Commercial and Multifamily Residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable, Gross, Commercial, Mortgage | 2,825,794 |  | 2,719,830 |  |  |
Loans Receivable, Gross, Commercial, Construction | 213,939 |  | 209,118 |  |  |
Commercial and Multifamily Residential [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable, Gross, Commercial, Mortgage | 79,336 |  | 89,231 |  |  |
Loans Receivable, Gross, Commercial, Construction | 958 |  | 1,565 |  |  |
Loans and Leases Receivable, Gross | 83,082 |  | 94,795 |  |  |
Commercial Portfolio Segment [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable, Gross, Commercial and Industrial | 2,748,868 |  | 2,571,239 |  |  |
Commercial Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable, Gross, Commercial and Industrial | 2,735,206 |  | 2,551,054 |  |  |
Commercial Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable, Gross, Commercial and Industrial | 13,662 |  | 20,185 |  |  |
Loans and Leases Receivable, Gross | 14,895 |  | 21,606 |  |  |
Real Estate Portfolio Segment [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable Real Estate Mortgage | 3,095,942 |  | 2,997,254 |  |  |
Real Estate Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable Real Estate Mortgage | 3,002,281 |  | 2,890,161 |  |  |
Real Estate Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable Real Estate Mortgage | 93,661 |  | 107,093 |  |  |
Loans and Leases Receivable, Gross | 99,780 |  | 115,438 |  |  |
One-to-Four Family Residential Construction [Domain] | Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans and Leases Receivable, Gross | 377 |  | 832 |  |  |
Real Estate Construction Portfolio Segment [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable Real Estate Construction | 360,693 |  | 333,402 |  |  |
Real Estate Construction Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable Real Estate Construction | 359,358 |  | 331,005 |  |  |
Real Estate Construction Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans Receivable Real Estate Construction | 1,335 |  | 2,397 |  |  |
Loans and Leases Receivable, Gross | 1,436 |  | 2,558 |  |  |
Consumer Portfolio Segment [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans and Leases Receivable, Gross, Consumer | 335,732 |  | 345,246 |  |  |
Allowance for loan losses | (3,673) | $ (3,551) | (3,534) | $ (3,743) | $ (3,559) | $ (3,531)
Consumer Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans and Leases Receivable, Gross, Consumer | 323,913 |  | 329,261 |  |  |
Loans and Leases Receivable, Gross | 321,503 |  | 324,522 |  |  |
Consumer Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member] |  |  |  |  |  |
Financing Receivable, Recorded Investment [Line Items] |  |  |  |  |  |
Loans and Leases Receivable, Gross, Consumer | 11,819 |  | 15,985 |  |  |
Loans and Leases Receivable, Gross | $ 13,039 |  | $ 17,649 |  |  |

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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://www.xbrl.org/2003/role/presentationRef -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 2: http://www.xbrl.org/2003/role/presentationRef -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 3: http://www.xbrl.org/2003/role/presentationRef -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 4: http://www.xbrl.org/2003/role/presentationRef -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 Reference 5: http://www.xbrl.org/2003/role/presentationRef -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 + Details
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