Income Taxes (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2018	Apr. 01, 2017	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income tax discrete benefits	$ (25,378)
Tax benefit from remeasurement of deferred tax liability	32,264
Tax Cuts and Jobs Act of 2017, income tax expense, accounting complete, mandatory deemed repatriation tax	6,886
Tax Cuts and Jobs Act of 2017, incomplete accounting, change in tax rate, provisional income tax benefit	32,244
Tax Cuts and Jobs Act of 2017, income tax benefit, accounting provisional, remeasurement of deferred tax assets and liabilities	$ 20
Full-year estimated annual effective tax rate, excluding impact of discrete items	17.30%	20.40%
Federal statutory income tax rate, percent	24.50%
Unrecognized tax benefits	$ 6,742		$ 5,849
Unrecognized tax benefits that would favorably impact the effective tax rate on continuing operations	$ 4,145		$ 3,234