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Derivative Financial Instruments - Summary of Collars Designated as Cash Flow Hedges (Detail) - USD ($) | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional amounts | $ 1,452,000,000 | $ 665,500,000
Variable Interest Rate Collar | Cash Flow Hedging | Derivatives designated as hedging instruments |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |
Notional amounts | $ 300,000,000 | $ 300,000,000
Weighted average cap rates | 3.21% | 3.21%
Weighted average floor rates | 2.21% | 2.21%
Weighted average rates | 0.15% | 1.70%
Weighted average maturity (in years) | 9 months 18 days | 1 year 10 months 24 days
Unrealized gains (losses) | $ 5,244,000 | $ 3,691,000

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- Definition Average cap rate on a group of interest rate derivatives, such as interest rate caps or collars. If market rates exceed the cap rate, a payment or receipt is triggered on the contract. + References No definition available. + Details
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- Definition Average floor rate on a group of interest rate derivatives, such as interest rate floor or collars. If market rates fall below the floor rate, a payment or receipt is triggered on the contract. + References No definition available. + Details
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- Definition Average remaining period until maturity of the derivative contract, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Nominal or face amount used to calculate payment on derivative. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959 + Details
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- Definition The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 + Details
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