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Share-based Compensation Arrangement by Share-based Payment Award, Shares, Expected to Vest, Percentage

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Share-based Compensation Arrangements By Share-based Payment Award, Award Amortization Period

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Share-based Compensation Arrangements By Share-based Payment Award, Number Of Award Tranches

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Share-based Compensation Arrangements By Share-based Payment Award, Performance Period

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Amount of cost for defined contribution plan.

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Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of cost (reversal of cost) for pension and other postretirement benefits.

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Amount of noncash expense for share-based payment arrangement.

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Amount of additional cost recognized for award under share-based payment arrangement from occurrence of event accelerating recognition of cost.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The maximum risk-free interest rate assumption that is used in valuing an option on its own shares.

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The minimum risk-free interest rate assumption that is used in valuing an option on its own shares.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Number of shares of stock issued as of the balance sheet date, including shares that had been issued and were previously outstanding but which are now held in the treasury.

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Share-Based Compensation and Other Benefit Plans - Summary of Share-Based Compensation Expense (Details) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 31, 2017 tranche	Sep. 30, 2019 USD ($) shares	Sep. 30, 2018 USD ($) shares	Sep. 30, 2019 USD ($) $ / shares shares	Sep. 30, 2018 USD ($) $ / shares shares	Dec. 31, 2018 USD ($)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Dividends \| $				$ 0	$ 0
Share-based compensation (equity-classified) \| $		$ 1,000	$ 1,000	3,101	3,472
Share-based Payment Arrangement, Accelerated Cost \| $					600
Separation Agreement, Consulting Fees \| $						$ 300
Defined Contribution Plan, Cost \| $		200	100	500	400
Other Pension, Postretirement and Supplemental Plans [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Pension and Other Postretirement Benefits Cost (Reversal of Cost) \| $		$ 100	$ 100	$ 100	$ 100
Time Vested Restricted Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant \| shares		357,147		357,147
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value \| $ / shares				$ 30.65	$ 65.96
Shares, Issued \| shares		42,534	53,411	42,534	53,411
Time Vested Restricted Stock Units [Member] \| Minimum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation Arrangements By Share-based Payment Award, Award Amortization Period				2 years
Time Vested Restricted Stock Units [Member] \| Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation Arrangements By Share-based Payment Award, Award Amortization Period				5 years
Performance Restricted Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant \| shares		0	98,526	0	98,526
Share-based Compensation Arrangements By Share-based Payment Award, Award Amortization Period				5 years
Shares, Issued \| shares		1,495	1,495	1,495	1,495
Share-based Compensation Arrangements By Share-based Payment Award, Performance Period	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Minimum				1.44%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate, Maximum				1.51%
Performance Restricted Stock Units [Member] \| Minimum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate				59.63%
Share-based Compensation Arrangements By Share-based Payment Award, Number Of Award Tranches \| tranche	2
Share-based Compensation Arrangement by Share-based Payment Award, Shares, Expected to Vest, Percentage				0.00%
Performance Restricted Stock Units [Member] \| Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate				62.18%
Share-based Compensation Arrangements By Share-based Payment Award, Number Of Award Tranches \| tranche	3
Share-based Compensation Arrangement by Share-based Payment Award, Shares, Expected to Vest, Percentage				200.00%
Performance Restricted Stock Units [Member] \| Year 1 [Member] \| Minimum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [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				$ 47.70
Performance Restricted Stock Units [Member] \| Year 2 [Member] \| Maximum [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [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				$ 65.28
Time Vested Restricted Stock Units - Employees [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant \| shares		9,707	42,459	9,707	42,459
Employees and Directors [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant \| shares		1,424,600		1,424,600