Stock-Based Compensation Narrative (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement [Line Items]
Compensation expense	$ 2,674	$ 1,035	$ 4,184	$ 1,769
Stock-based compensation expense, net of tax benefit	$ 1,599	$ (905)	$ 2,648	$ (915)
Directors' Plan [Member]
Statement [Line Items]
Shares reserved for future grants under the stock option and compensation plan	329		329
Employee Equity Plan [Member]
Statement [Line Items]
Awards vesting period (in years)			3 years
Shares reserved for future grants under the stock option and compensation plan	10,600		10,600