Debt (Schedule of Long-Term Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Jan. 31, 2013
Debt Instrument [Line Items]
Total debt	$ 210,021	$ 209,637
Unamortized original issue discount	(2,379)	(3,163)
Less current maturities	400	400
Total long-term debt	209,621	209,237
Senior Subordinated 6.25% Notes
Debt Instrument [Line Items]
Total debt	$ 210,000	$ 210,000
Senior Subordinated Notes, interest rate	6.25%	6.25%	6.25%
Other debt
Debt Instrument [Line Items]
Total debt	$ 2,400	$ 2,800