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Significant Accounting Policies - Impact of new financial accounting standards (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Mar. 31, 2019 | Jun. 30, 2019 | Jan. 01, 2019
Recently Issued Accounting Standards |  |  |
Lease, Practical Expedients, Package [true false] |  | true |
Lease, Practical Expedient, Use of Hindsight [true false] |  | false |
Right of use asset |  | $ 10,426 |
Lease liability |  | $ 10,531 |
Accounting Standards Update 2017-12 |  |  |
Recently Issued Accounting Standards |  |  |
Transferred securities from held to maturity to available-for-sale | $ 573,600 |  |
Accounting Standards Update 2016-02 | Restatement |  |  |
Recently Issued Accounting Standards |  |  |
Right of use asset |  |  | $ 8,100
Lease liability |  |  | $ 8,100

X
- Definition Amount of investment in debt security, measured at amortized cost, transferred to investment in debt security, measured at fair value, with change in fair value recognized in other comprehensive income (available-for-sale) and net income (trading). + References No definition available. + Details
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- Definition Indicates (true false) whether practical expedient is elected to use hindsight in determining lease term and in assessing impairment of right-of-use asset. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 10 -Section 65 -Paragraph 1 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=119364159&loc=SL77916155-209984 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 10 -Section 65 -Paragraph 1 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=119364159&loc=SL77916155-209984 + Details
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- Definition Indicates (true false) whether practical expedients are elected for not reassessing whether any expired or existing contract is or contains lease, lease classification for expired or existing lease, and initial direct cost for any existing lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 10 -Section 65 -Paragraph 1 -Subparagraph (j) -URI http://asc.fasb.org/extlink&oid=119364159&loc=SL77916155-209984 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 10 -Section 65 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=119364159&loc=SL77916155-209984 + Details
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- Definition Present value of lessee's discounted obligation for lease payments from operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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- Definition Amount of lessee's right to use underlying asset under operating lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977 + Details
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