Other Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017
Other Liabilities Disclosure [Abstract]
Accrued bonus and deferred compensation	$ 19,616		$ 41,508
Customer deposits	16,232		14,903
Accrued interest	14,609		14,401
Accrued warranty expense	12,585	$ 13,432	15,331	$ 14,583	$ 15,816	$ 18,091
Litigation accrual	3,294		3,656
Income tax liabilities	961		710
Other	31,723		35,880
Total	$ 99,020		$ 126,389