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Stock-based Compensation Plans (Narrative) (Details) $ / shares in Units, $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2019 USD ($) $ / shares shares | Dec. 31, 2018 USD ($) shares | Sep. 30, 2019
Share-based Payment Arrangement, Expense | $ | $ 1.9 | $ 1.7 |
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount | $ | $ 11.8 |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | 108,976 | 165,467 |
Phantom Share Units (PSUs) [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instrument Other than Option, Nonvested, Intrinsic Value | $ / shares | $ 11.98 |  |
Share-based compensation liability | $ | $ 1.0 |  |
Granted, shares | 188,973 |  |
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, Weighted Average Grant Date Fair Value | $ / shares | $ 11.26 |  |
Granted, shares | 188,973 |  |
Performance Shares [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period | 93,647 | 181,065 |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | 196,284 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  | 3 years
Share-based compensation, units awarded but not yet granted | 218,292 |  |
Restricted Stock Units (RSUs) [Member] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period | 132,303 |  |
Granted, shares | 162,433 |  |
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, Weighted Average Grant Date Fair Value | $ / shares | $ 11.26 |  |
Granted, shares | 162,433 |  |
Market Based Performance Shares |  |  |
Granted, shares | 147,213 |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate | 1870000.00% |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ / shares | $ 14.94 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate | 1530000.00% |  |
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term | 2 years 9 months 29 days |  |
Granted, shares | 147,213 |  |
Minimum [Member] | Performance Shares [Member] |  |  |
Performance Factors | 0 |  |
Minimum [Member] | Market Based Performance Shares |  |  |
Performance Factors | 0 |  |
Maximum [Member] | Performance Shares [Member] |  |  |
Performance Factors | 2 |  |
Maximum [Member] | Market Based Performance Shares |  |  |
Performance Factors | 2 |  |
Share-based Payment Arrangement, Tranche One [Member] | Performance Shares [Member] |  |  |
Granted, shares | 58,040 |  |
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, Weighted Average Grant Date Fair Value | $ / shares | $ 11.26 |  |
Granted, shares | 58,040 |  |
Share-based Payment Arrangement, Tranche Two [Member] | Performance Shares [Member] |  |  |
Granted, shares | 102,203 |  |
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, Weighted Average Grant Date Fair Value | $ / shares | $ 11.26 |  |
Granted, shares | 102,203 |  |
Share-based Payment Arrangement, Tranche Three [Member] | Performance Shares [Member] |  |  |
Granted, shares | 44,451 |  |
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, Weighted Average Grant Date Fair Value | $ / shares | $ 11.26 |  |
Granted, shares | 44,451 |  |

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