Equity-based Compensation - Additional Stock Option Information (Details) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amount collected from stock option exercises	$ 0	$ 822,000	$ 306,000
Total intrinsic value of stock option exercises	0	370,000	47,000
Tax benefit of stock option exercises recorded in income tax expense	1,556,000	63,000	0
Tax benefit of stock option exercises recorded in additional paid-in-capital	0	0	315,000
Aggregate intrinsic value of outstanding stock options	0	386,000	102,000
Aggregate intrinsic value of exercisable stock options	$ 0	$ 386,000	$ 102,000
Share price (in dollars per share)	$ 16.32	$ 25.43	$ 23.7
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expense recorded	$ 0	$ 0	$ 100,000

Adjustments to Income Tax Expense, Income Tax Deficiency from Share-based Compensation

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Amount of increase in additional paid in capital (APIC) resulting from a tax benefit associated with share-based compensation plan other than an employee stock ownership plan (ESOP). Includes, but is not limited to, excess tax benefit.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Amount of cash inflow from exercise of stock options granted under share-based compensation arrangement.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Price of a single share of a number of saleable stocks of a company.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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