Trade and Finance Receivables - Trade Receivables (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivables, less allowances with Iranian customers			$ 246,468,000	$ 217,420,000	$ 278,167,000
Iranian customers
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivables, less allowances with Iranian customers			7,000,000	8,000,000	14,000,000
Iranian customers | Customer not able to find acceptable methods of payment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trade receivables reserved amounts related to customers	$ 2,000,000	$ 9,000,000