Derivative Instruments - Swap Agreements by Counterparty (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Chicago Mercantile Exchange
Derivative [Line Items]
Notional Amount	$ 2,191,000	$ 3,306,000
Interest rate swap agreements
Derivative [Line Items]
Notional Amount	$ 2,191,000	$ 3,306,000

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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