Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
Income taxes paid, net of refunds		$ 2,065	$ (10,587)	$ 4,909
Net tax benefit recorded due to change in corporate tax rate	$ 73,500
One-time mandatory charge relating to previously recognized deferred earnings in foreign subsidiaries	1,400
Credit resulting from remeasurement of deferred tax liability	74,900
Net deferred tax assets	121,730	121,730	182,113
Tax credits carryforward general business	7,100	7,100
Tax credit carryforwards foreign		3,100
Deferred tax benefit			2,600
Current tax provision benefit		(100)	(882)	$ 2,775
Penalties and interest liabilities	300	300	400
Penalties and interest expense		100	200
Scenario, Forecast
Operating Loss Carryforwards [Line Items]
Decrease in reserve during next 12 due to settling of state tax appeals and lapse of statue of limitations					$ (200)
Expiration Begins, 2034
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	15,700	15,700
Expiration Begins, 2018
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	81,900	81,900
Expiration Begins, 2035
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards	100	100
Latest Tax Year
Operating Loss Carryforwards [Line Items]
Current tax provision benefit			1,800
Railroad Track Maintenance Credits
Operating Loss Carryforwards [Line Items]
Railroad track maintenance credits deferred to future periods			$ 6,000
U.S.
Operating Loss Carryforwards [Line Items]
Net deferred tax assets	122,000	$ 122,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Non-cash charge to income tax expense for additional valuation allowance	$ 600