Income Taxes - Additional Information (Details) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 01, 2018	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Sep. 30, 2018	Dec. 31, 2017
Income Taxes [Line Items]
United States statutory tax rate	21.00%	24.50%	35.00%		35.00%		35.00%
Valuation allowance for deferred tax assets or provision for income taxes		$ 0		$ 0
Company's effective tax rates		12.50%	(3.10%)	4.50%	(3.50%)
Amended prior year tax return, refund claim amount		$ 700,000
Scenario, Plan
Income Taxes [Line Items]
United States statutory tax rate						24.50%