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Activity in Allowance for Losses on Non-Covered Loans (Detail) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Valuation Allowance [Line Items] |  |  |
Balance, beginning of period | $ 158,290 | $ 147,124 |
Charge-offs | (63,350) | (3,583) |
Recoveries | 2,163 | 2,875 |
Provision for (recovery of) non-covered loan losses | 37,242 | 4,180 | $ (15,004)
Balance, end of period | 158,046 | 158,290 | 147,124
Non-Covered Loans |  |  |
Valuation Allowance [Line Items] |  |  |
Provision for (recovery of) non-covered loan losses | 60,943 | 11,874 | (3,334)
Mortgage Receivable |  |  |
Valuation Allowance [Line Items] |  |  |
Balance, beginning of period | 125,416 | 124,478 |
Charge-offs | (375) | (170) |
Recoveries | 605 | 1,272 |
Balance, end of period | 128,275 | 125,416 | 124,478
Mortgage Receivable | Non-Covered Loans |  |  |
Valuation Allowance [Line Items] |  |  |
Provision for (recovery of) non-covered loan losses | 2,629 | (164) |
Other loans |  |  |
Valuation Allowance [Line Items] |  |  |
Balance, beginning of period | 32,874 | 22,646 |
Charge-offs | (62,975) | (3,413) |
Recoveries | 1,558 | 1,603 |
Balance, end of period | 29,771 | 32,874 | $ 22,646
Other loans | Non-Covered Loans |  |  |
Valuation Allowance [Line Items] |  |  |
Provision for (recovery of) non-covered loan losses | $ 58,314 | $ 12,038 |

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- Definition Amount of recovery of financing receivables doubtful of collection that were previously charged off. + 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 (c)(4) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
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- Definition Amount of direct write-downs of financing receivables charged against the allowance. + 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 (c)(3) -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524 + Details
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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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