Quarterly report pursuant to Section 13 or 15(d)

Share-Based Payments - Narrative (Details)

v3.19.1
Share-Based Payments - Narrative (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 2019
Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total stock-based compensation cost $ 1,366 $ 2,658 $ 5,013 $ 8,132
Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Percent of shares vested on time     40.00%  
Unrecognized compensation cost on non-vested awards $ 10,777   $ 10,777  
Weighted average period of recognition of unrecognized compensation cost on non-vested awards     2 years 2 months  
Restricted stock awards unvested (in shares) 34,542   34,542  
Restricted Stock | Minimum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Expiration period     3 years  
Restricted Stock | Maximum        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Expiration period     5 years  
Restricted Stock | After 3 Years        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting increment     50.00%  
Restricted Stock | Attainment of Pre-Defined Levels of Appreciation in Market Value        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting increment     25.00%  
Restricted Stock | Attainment of Pre-Defined Levels of Adjusted Earnings Per Share        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting increment     25.00%  
2017 Equity Incentive Plan | Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares granted under the 2017 Equity incentive plan     262,200  
2017 Equity Incentive Plan | Stock Compensation Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Term of plan     10 years  
Maximum number of shares available for grants or awards (in shares) 1,700,000   1,700,000  
Shares reserved for future issuance under award plan (in shares) 1,700,000   1,700,000  
Retirement Eligible Employees        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total stock-based compensation cost     $ 1,849 2,850
Future income tax benefit from compensation expense recognized $ 335 $ 651 870 $ 1,521
2014 Director Fee Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Annual retainer fee paid to non-employee directors     85  
Annual retainer fee paid to non-employee Chairman of the Board     $ 185  
2019 Director Fee Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Maximum number of shares available for grants or awards (in shares) 150,000   150,000  
Director Fee Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares deferred under stock based compensation plan (in shares) 25,498   25,498  
Value of annual stock based grant     $ 125  
Total restricted stock awards granted to date (in shares) 196,266   196,266  
Restricted stock awards unvested (in shares) 23,037   23,037