Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Deferred tax assets:
Loss and credit carryforwards	$ 24,400	$ 34,383
Compensation benefits	30,388	45,823
Property and equipment	0	3,476
Other assets	9,674	12,239
Deferred tax assets, gross	64,462	95,921
Less valuation allowance	(19,564)	(17,657)
Total deferred tax assets	44,898	78,264
Deferred tax liabilities:
Intangible assets	(15,921)	(25,346)
Property and equipment	(2,616)	0
Other liabilities	(6,229)	(5,714)
Total deferred tax liabilities	(24,766)	(31,060)
Deferred tax assets, net	$ 20,132	$ 47,204