CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
CONSOLIDATED BALANCE SHEETS
Accumulated depreciation	$ 118,248	$ 113,520
Accumulated amortization	$ 113,507	$ 107,247
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	50,000,000	50,000,000
Common stock, shares issued	30,596,940	30,596,940
Treasury stock, shares	4,615,627	4,615,627