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v3.21.2

Stock-based Compensation Plans (Schedule of Shared-Based Compensation, Performance Units (Details) - $ / shares |  |  |  |  |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | --- | ---
Jan. 27, 2021 | Dec. 02, 2020 | Feb. 24, 2020 | Jan. 28, 2020 | Dec. 03, 2019 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period |  |  |  |  |  |  |  |  |  |  |  |  |  | 61,610 |  |  |
Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity |  |  |  |  |  |  |  |  |  |  |  |  | Restricted stock unit activity under the 2006 Plan is summarized below.
| Restricted stock units |  | Weighted average grant date fair value per unit |  | Weighted average remaining contractual term (years) |  | Aggregate intrinsic value (millions)
Outstanding at September 30, 2018 | 481,562 |  |  | $ | 12.14 |  |  | 1.0 |  |
Granted | 233,830 |  |  | 10.10 |  |  |  |  |
Vested | (259,107) |  |  | 11.75 |  |  |  |  | $ | 2.6 |
Cancelled | (19,263) |  |  | 11.43 |  |  |  |  |
Outstanding at September 30, 2019 | 437,022 |  |  | 11.31 |  |  | 0.9 |  |
Granted | 301,979 |  |  | 11.55 |  |  |  |  |
Vested | (295,241) |  |  | 11.40 |  |  |  |  | $ | 3.4 |
Cancelled | (35,254) |  |  | 11.48 |  |  |  |  |
Outstanding at September 30, 2020 | 408,506 |  |  | 11.41 |  |  | 0.9 |  |
Granted | 220,795 |  |  | 12.29 |  |  |  |  |
Vested | (228,121) |  |  | 11.62 |  |  |  |  | $ | 2.8 |
Cancelled | (5,083) |  |  | 11.41 |  |  |  |  |
Outstanding at September 30, 2021 | 396,097 |  |  | $ | 11.78 |  |  | 0.8 |  |
Performance Shares [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period |  |  |  |  |  |  |  |  |  |  |  |  | 62,396 |  | 109,380 |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  |  | 103,058,000,000 | 93,647 |  |  |
Market Based Performance Shares Member |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | 4,187 | 234,199 | 7,498 | 2,763 | 147,213 |  |  |  |  |  |  |  |  |  |  |  |
Dividend yield | 1.84% | 1.77% | 1.73% | 1.76% | 1.87% |  |  |  |  |  |  |  |  |  |  |  |
Risk-free interest rate | 0.16% | 0.21% | 1.23% | 1.44% | 1.53% |  |  |  |  |  |  |  |  |  |  |  |
Expected life (years) | 2 years 8 months 1 day | 2 years 9 months 29 days | 2 years 7 months 6 days | 2 years 8 months 1 day | 2 years 9 months 29 days |  |  |  |  |  |  |  |  |  |  |  |
Granted, Weighted average grant date fair value per share | $ 14.26 | $ 15.39 | $ 18.17 | $ 16.76 | $ 14.94 |  |  |  |  |  |  |  |  |  |  |  |
Share-based Payment Arrangement, Tranche One [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  |  | 57,092 |  |  |  |  |  |  |  |  |
2017 member [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 10.53 | $ 12.50 | $ 13.26
2017 member [Member] | Share-based Payment Arrangement, Tranche One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100.00%
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  |  | 54,006 |  |  |  |
2017 member [Member] | Share-based Payment Arrangement, Tranche One [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  |  |  |  | 59,285 |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (5,279) |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 54,006 |
2017 member [Member] | Share-based Payment Arrangement, Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 135.70% |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  |  | 26,294 |  |  |  |
2017 member [Member] | Share-based Payment Arrangement, Tranche Two [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  |  |  |  | 59,286 |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  |  |  | (39,910) |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 19,376 |  |
2017 member [Member] | Share-based Payment Arrangement, Tranche Three [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 64.50% |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  |  | 12,501 |  |  |  |
2017 member [Member] | Share-based Payment Arrangement, Tranche Three [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  |  |  |  | 59,290 |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  |  | (39,909) |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  |  | 19,381 |  |  |
January 23, 2017 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 13.15
January 23, 2017 [Member] | Share-based Payment Arrangement, Tranche One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100.00%
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  |  | 19,012 |  |  |  |
January 23, 2017 [Member] | Share-based Payment Arrangement, Tranche One [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  |  |  | 19,012 |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 19,012 |
January 23, 2017 [Member] | Share-based Payment Arrangement, Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 135.70% |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  |  | 25,798 |  |  |  |
January 23, 2017 [Member] | Share-based Payment Arrangement, Tranche Two [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  |  |  | 19,011 |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 | 0 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  |  | 19,011 | 19,011 |  |
January 23, 2017 [Member] | Share-based Payment Arrangement, Tranche Three [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 64.50% |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  |  | 12,263 |  |  |  |
January 23, 2017 [Member] | Share-based Payment Arrangement, Tranche Three [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  |  |  | 19,011 |  |  |  |  |  |  |  |
November 28, 2017 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 11.26 | $ 10.53 | $ 12.50 |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  | 35,425 | 52,299 |  |  |
November 28, 2017 [Member] | Share-based Payment Arrangement, Tranche One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 135.70% |
November 28, 2017 [Member] | Share-based Payment Arrangement, Tranche One [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 0 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 57,092 |  |
November 28, 2017 [Member] | Share-based Payment Arrangement, Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 64.50% |  |
November 28, 2017 [Member] | Share-based Payment Arrangement, Tranche Two [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  |  | 57,092 |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  |  | (4,793) |  |  |
November 28, 2017 [Member] | Share-based Payment Arrangement, Tranche Three [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  |  | 90.90% |  |  |
November 28, 2017 [Member] | Share-based Payment Arrangement, Tranche Three [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  |  | 57,104 |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  | (21,679) |  |  |  |
November 27, 2018 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value |  |  |  |  |  |  |  |  |  |  |  |  | $ 11.86 | $ 11.26 | $ 10.53 |  |
November 27, 2018 [Member] | Share-based Payment Arrangement, Tranche One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  |  | 102,203 |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 64.50% |  |
November 27, 2018 [Member] | Share-based Payment Arrangement, Tranche One [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  | 110,954 |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  |  | (8,751) |  |  |
November 27, 2018 [Member] | Share-based Payment Arrangement, Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  | 97,772 |  |  |  |
November 27, 2018 [Member] | Share-based Payment Arrangement, Tranche Two [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  | 110,954 |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  | (13,182) |  |  |  |
November 27, 2018 [Member] | Share-based Payment Arrangement, Tranche Three [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  | 82,489 |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  | 116.10% | 90.90% |  |  |
November 27, 2018 [Member] | Share-based Payment Arrangement, Tranche Three [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  | 110,967 |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  | (28,478) |  |  |  |
December 3, 2019 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value |  |  |  |  |  |  |  |  |  |  |  |  | $ 11.86 | $ 11.26 |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  | 60,375 |  |  |  |
December 3, 2019 | Share-based Payment Arrangement, Tranche One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  | 67,597 |  |  |  |
December 3, 2019 | Share-based Payment Arrangement, Tranche One [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  | 69,988 |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  |  | (2,391) |  |  |  |
December 3, 2019 | Share-based Payment Arrangement, Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number |  |  |  |  |  |  |  |  |  |  |  |  | 60,375 |  |  |  |
December 3, 2019 | Share-based Payment Arrangement, Tranche Two [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  | 69,989 |  |  |  |  |  |  |  |  |  |  |
December 3, 2019 | Share-based Payment Arrangement, Tranche Three [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Performance Factor |  |  |  |  |  |  |  |  |  |  |  |  | 116.10% | 90.90% |  |  |
December 3, 2019 | Share-based Payment Arrangement, Tranche Three [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  | 69,989 |  |  |  |  |  |  |  |  |  |  |
Forecast [Member] | November 28, 2017 [Member] | Share-based Payment Arrangement, Tranche One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  | 77,474 |  |  |  |  |
Forecast [Member] | November 28, 2017 [Member] | Share-based Payment Arrangement, Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  | 33,733 |  |  |  |  |
Forecast [Member] | November 28, 2017 [Member] | Share-based Payment Arrangement, Tranche Three [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  | 32,202 |  |  |  |  |
Forecast [Member] | November 27, 2018 [Member] | Share-based Payment Arrangement, Tranche One [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  | 65,921 |  |  |  |  |
Forecast [Member] | November 27, 2018 [Member] | Share-based Payment Arrangement, Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  | 88,875 |  |  |  |  |
Forecast [Member] | November 27, 2018 [Member] | Share-based Payment Arrangement, Tranche Three [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  |  | 95,770 |  |  |  |  |
Forecast [Member] | December 3, 2019 | Share-based Payment Arrangement, Tranche Two [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  | 61,446 |  |  |  |  |  |
Forecast [Member] | December 3, 2019 | Share-based Payment Arrangement, Tranche Two [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  |  | (9,614) |  |  |  |  |
Forecast [Member] | December 3, 2019 | Share-based Payment Arrangement, Tranche Three [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Settlement of performance-based restricted stock units, net of shares withheld for taxes |  |  |  |  |  |  |  |  |  |  | 70,096 |  |  |  |  |  |
Forecast [Member] | December 3, 2019 | Share-based Payment Arrangement, Tranche Three [Member] | PRSU base units [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period |  |  |  |  |  |  |  |  |  |  | (9,614) |  |  |  |  |  |

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