Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of accounting change	$ 2,504,473	$ 2,161,598		$ 2,197,219	$ 2,209,287	$ 2,052,394	$ 1,987,720
Accounts receivable, allowance for credit loss	$ 5,171			11,143
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of accounting change				$ 6,074
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of accounting change			$ 6,000
Accounts receivable, allowance for credit loss			$ (8,000)