Share-Based Compensation - Narrative (Details) - USD ($)	1 Months Ended		3 Months Ended		12 Months Ended
	Feb. 28, 2019	Feb. 28, 2018	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Repurchase of common stock for employee tax withholding obligations amount, shares			24,067	16,362
Repurchase of common stock for employee tax withholding obligations amount			$ 2,905,000	$ 868,000
2017 Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Useful Life of the plan			10 years
Common stock shares issuable			1,750,000
Shares available for grant			1,580,999
2007 Plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Award vesting period			3 years
2007 Plan | Performance Unit Incentive Plan (“PUP”)
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Awards with grant date fair value during the period			$ 4,300,000
Stock value payable			1,700,000
Liability awards recorded			2,700,000		$ 7,000,000
Payments to employees			$ 5,600,000		5,900,000
Repurchase of common stock for employee tax withholding obligations amount, shares			25,771
Repurchase of common stock for employee tax withholding obligations amount			$ 1,500,000
Paid to employees as shares			$ 3,400,000
2007 Plan | Restricted Stock
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Repurchase of common stock for employee tax withholding obligations amount, shares			24,067	16,362
Repurchase of common stock for employee tax withholding obligations amount			$ 1,400,000	$ 900,000
Unamortized cost			$ 4,900,000
Recognition period of unrecognized cost			1 year 8 months 12 days
2007 Plan | Restricted Stock Units
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Payments to employees	$ 300,000	$ 200,000
Liabilities related to restricted stock			$ 200,000		$ 400,000
Restructuring Charges
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation before income tax benefit			$ 0	$ 0