Income Taxes - Schedule of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended													12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2018	Sep. 30, 2017	Sep. 30, 2016
Current:
Federal					$ 630									$ 11,284	$ 16,198	$ 13,209
State					862									5,129	1,236	664
Current income tax provision					1,492									16,413	17,434	13,873
Deferred:
Federal					7,530									(4,901)	(1,454)	2,743
State					(39)									(589)	28	187
Deferred income tax provision (benefit)					7,491									(5,490)	(1,426)	2,930
Total continuing operations	$ 3,123	$ 6,956	$ (2,961)	$ 3,805	$ 8,983	$ 194	$ 5,934	$ 5,012	$ 4,868	$ 4,611	$ 4,052	$ 4,281	$ 3,859	$ 10,923	$ 16,008	$ 16,803