Recently Issued and Adopted Accounting Standards - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Oct. 01, 2019	Sep. 30, 2019
Operating lease right-of-use  assets	$ 463
Lease liabilities	$ 552
Accounting Standards Update 2018-11 [Member]
Operating lease right-of-use  assets		$ 652,686	$ 116,213
Lease liabilities		$ 768,899