Accounts and Notes Receivable and Credit Quality of Notes Receivable - Modification of Terms (Details) (Notes receivable, USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014 contract customer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers	9
Number of notes	28
Pre-modification investment	$ 12.8
Post-modification investment	12.8
International
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers	9	[1]
Number of notes	28	[1]
Pre-modification investment	12.8	[1]
Post-modification investment	12.8	[1]
International | Customer one
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers	1
Post-modification investment	4.0
Number of notes consolidated into one	12
Contract extension term	28 months
International | Customer two
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers	1
Post-modification investment	2.3
Contract extension term	9 months
International | Customer Three
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers	1
International | Customer three, note two
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-modification investment	0.2
Contract extension term	7 months
International | Customer three, note one
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-modification investment	1.4
Number of notes consolidated into one	4
Contract extension term	5 months
International | Customer four
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers	1
Post-modification investment	3.1
Number of notes consolidated into one	3
Contract extension term	4 months
International | Customer five
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers	1
Post-modification investment	0.5
Contract extension term	21 months
International | Customer six
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers	1
Post-modification investment	0.3
Contract extension term	27 months
International | Customer seven
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers	1
Post-modification investment	0.1
Contract extension term	21 months
International | Customer eight
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-modification investment	0.7
Number of notes consolidated into one	2
Contract extension term	15 months
International | Customer nine
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-modification investment	$ 0.2
Number of notes consolidated into one	2
Contract extension term	14 months

[1] The modifications are detailed below: •One customer for which 12 notes were consolidated into one note aggregating $4.0 million, with an average 28-month payment extension; •One customer for which three notes were consolidated into one note aggregating $3.1 million, with an average four-month payment extension; •One customer with a note for $2.3 million for which original payment terms were extended by nine months;•One customer for which four notes were consolidated into one note aggregating $1.4 million, with an average five-month extension, and another note for $0.2 million for which original payment terms were extended by seven months;•One customer for which two notes were consolidated into one note aggregating $0.7 million, with an average 15-month payment extension;•One customer with a note for $0.5 million for which original payment terms were extended by 21 months; •One customer with a note for $0.3 million for which original payment terms were extended by 27 months; •One customer for which two notes were consolidated into one note aggregating $0.2 million, with an average 14-month payment extension; and•One customer with a note for $0.1 million for which original payment terms were extended by 21 months.