Summary of Significant Accounting Policies (ASC 606 Balance Sheet) (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Sep. 30, 2018		Sep. 30, 2017	Sep. 30, 2016
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net		$ 56,417	$ 49,819	[1]	$ 28,855
Property, equipment and improvements, net		13,857	8,354	[1]	13,241
Deferred tax assets		7,330	6,600	[1]	9,278
Unearned revenue current			3,177		1,812
Other non-current liabilities		3,809	720	[1]	807
Retained earnings		$ 161,919	151,961	[1]	150,363
As reported
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net			50,817		28,855
Property, equipment and improvements, net			6,270		12,801
Deferred tax assets			6,665		9,211
Unearned revenue current			2,579		1,343
Other non-current liabilities			510		654
Retained earnings			151,748		150,478
ASU 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative-effect adjustment from adoption of new accounting policy						$ (152)
ASU 2014-09 | Impact of Adoption
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable, net			(998)		0
Property, equipment and improvements, net			2,084		440
Deferred tax assets			(65)		67
Unearned revenue current			598		469
Other non-current liabilities			210		153
Retained earnings			$ 213		$ (115)
Retained Earnings | ASU 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative-effect adjustment from adoption of new accounting policy	[1]					$ (152)

[1] Prior period information has been restated for the adoption of ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)”, which we adopted on October 1, 2018.