Other Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016
Other Liabilities Disclosure [Abstract]
Accrued bonus and deferred compensation	$ 29,541		$ 36,753
Customer deposits	20,714		11,704
Accrued interest	24,367		11,024
Accrued warranty expense	15,290	$ 14,583	18,091	$ 19,822	$ 25,386	$ 39,131
Litigation accrual	2,749		3,899
Income tax liabilities	867		811
Other	31,194		25,377
Total other liabilities	$ 124,722		$ 107,659