Income Taxes - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Tax Credit Carryforward [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 28,000,000
Total effective tax rate	31.30%	31.50%	31.50%
United States statutory rate	35.00%	35.00%	35.00%
Unrecognized Tax Benefits, Decreases Resulting from Prior Period Tax Positions	(707,000)	(337,000)	(8,193,000)
Net gain on sales of property and equipment	(1,165,000)	450,000	(584,000)
Unremitted Earnings of Foreign Subsidiaries To Be Indefinitely Reinvested	573,000,000
Unrecognized Tax Benefits, Probability Threshold of Realizing for Tax Benefits Recognition, Minimum Percentage	50.00%
Penalties and interest expense relating to uncertain tax positions	(400,000)	1,700,000	(2,700,000)
Liabilities for penalties and interest on uncertain tax	$ 2,900,000	$ 3,300,000