Revenue Recognition - Schedule of Impact of Adoption on Condensed Consolidated Statement of Balance Sheet (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
ASSETS
Prepaid expenses and other current assets	$ 48,657	$ 35,451
Deferred charges and other assets, net	18,774	13,067
Liabilities
Deferred tax liabilities, net	24,367	21,206
Partners’ capital
Common unitholders	328,633	329,129
General partner	(1,416)	$ (1,303)
Balances Without Adoption of ASC 606 | ASU 2014-09
ASSETS
Prepaid expenses and other current assets	41,823
Deferred charges and other assets, net	12,182
Liabilities
Deferred tax liabilities, net	20,599
Partners’ capital
Common unitholders	319,037
General partner	(1,478)
Effect of Change Higher/(Lower) | ASU 2014-09
ASSETS
Prepaid expenses and other current assets	6,834
Deferred charges and other assets, net	6,592
Liabilities
Deferred tax liabilities, net	3,768
Partners’ capital
Common unitholders	9,596
General partner	$ 62