Common Stock and Stock Compensation (Details)	1 Months Ended	3 Months Ended		6 Months Ended
	Dec. 31, 2019 USD ($)	Mar. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) director shares	Mar. 31, 2020 USD ($) $ / shares shares	Sep. 30, 2019 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, period	3 years
Common stock repurchased and retired | $		$ 4,195,000	$ 963,000
Share price (in dollars per share) | $ / shares		$ 6.46		$ 6.46
Common Stock Class A Non-voting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock repurchase program, amount authorized | $	$ 60,000,000.0		$ 60,000,000.0
Common stock repurchased and retired (in shares) | shares		800,740		943,149
Common stock repurchased and retired | $		$ 4,200,000		$ 5,200,000
Long-Term Incentive Plan 2010 | Common Stock Class A Non-voting
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (shares) | shares					5,485,649
Non-employee Directors | Long-Term Incentive Plan 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of directors | director			9
Non-employee Directors | Long-Term Incentive Plan 2010 | Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted in period (in shares) | shares			222,912