Stock-based Compensation Plans (Schedule of Shared-Based Compensation, Performance Units (Details)	3 Months Ended						12 Months Ended
	Dec. 31, 2018 shares	Dec. 31, 2017 shares	Mar. 31, 2017 shares	Dec. 31, 2016 shares	Dec. 31, 2015 shares	Dec. 31, 2014 shares	Sep. 30, 2021 shares	Sep. 30, 2020 shares	Sep. 30, 2019 $ / shares shares	Sep. 30, 2018 $ / shares shares	Sep. 30, 2017 $ / shares shares	Sep. 30, 2016 $ / shares shares	Sep. 30, 2015 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period										86,516
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									109,380		160,063
Settlement of performance-based restricted stock units, net of shares withheld for taxes									332,875	146,061
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
2015 [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 \| $ / shares											$ 13.26
2015 [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, Nonvested, Weighted Average Grant Date Fair Value \| $ / shares												$ 9.38	$ 9.78
2015 [Member] \| Share-based Payment Arrangement, Tranche One [Member] \| Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Factor													0.000
Settlement of performance-based restricted stock units, net of shares withheld for taxes										0
2015 [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						80,233
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period													(3,835)
Settlement of performance-based restricted stock units, net of shares withheld for taxes										76,398
2015 [Member] \| Share-based Payment Arrangement, Tranche Two [Member] \| Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Factor												1.021
Settlement of performance-based restricted stock units, net of shares withheld for taxes										75,327
2015 [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						80,229
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period												(6,447)
Settlement of performance-based restricted stock units, net of shares withheld for taxes										73,782
2015 [Member] \| Share-based Payment Arrangement, Tranche Three [Member] \| Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Factor											1.000
Settlement of performance-based restricted stock units, net of shares withheld for taxes										68,556
2015 [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						80,229
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period											(11,673)
Settlement of performance-based restricted stock units, net of shares withheld for taxes										68,556
2016 [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 \| $ / shares										$ 12.50	$ 13.26
2016 [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, Nonvested, Weighted Average Grant Date Fair Value \| $ / shares												$ 9.38
2016 [Member] \| Share-based Payment Arrangement, Tranche One [Member] \| Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Factor												1.021
Settlement of performance-based restricted stock units, net of shares withheld for taxes									75,375
2016 [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					77,823
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period												(3,998)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number												73,825
2016 [Member] \| Share-based Payment Arrangement, Tranche Two [Member] \| Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Factor											1.000
Settlement of performance-based restricted stock units, net of shares withheld for taxes									73,827
2016 [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					77,824
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period											(3,997)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number											73,827
2016 [Member] \| Share-based Payment Arrangement, Tranche Three [Member] \| Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Factor										1.357
Settlement of performance-based restricted stock units, net of shares withheld for taxes									21,689
2016 [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					77,824
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period										(61,841)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number										15,983
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 \| $ / shares									$ 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											1.000
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										1.357
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									0.645
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 \| $ / shares											$ 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											1.000
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										1.357
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
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									0.645
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
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period									0
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 \| $ / shares									$ 10.53	$ 12.50
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period									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										1.357
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, Grants in Period										57,092
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period										0
November 28, 2017 [Member] \| Share-based Payment Arrangement, Tranche Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Factor									0.645
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] \| 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									(4,796)
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 \| $ / shares									$ 10.53
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period									102,203
November 27, 2018 [Member] \| Share-based Payment Arrangement, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance Factor									0.645
Settlement of performance-based restricted stock units, net of shares withheld for taxes									65,921
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] \| 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 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									(8,755)
Forecast [Member] \| 2017 member [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								54,006
Forecast [Member] \| 2017 member [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								26,294
Forecast [Member] \| 2017 member [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								12,501
Forecast [Member] \| January 23, 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								19,012
Forecast [Member] \| January 23, 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								25,798
Forecast [Member] \| January 23, 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								12,263
Forecast [Member] \| 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, Grants in Period								52,308
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 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, Grants in Period							102,212	102,203