Accounts and Notes Receivable and Credit Quality of Notes Receivable (Modification of Terms) (Details) - Notes receivable $ in Millions		6 Months Ended
		Jun. 30, 2015 USD ($) customer contract	Jun. 30, 2014 USD ($) customer contract
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers | customer		7
Number of notes | contract		24
Pre-modification investment		$ 11.9
Post-modification investment		$ 11.9
International
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers | customer	[1]	7
Number of notes | contract	[1]	24
Pre-modification investment	[1]	$ 11.9
Post-modification investment	[1]	$ 11.9
International | Customer four
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers | customer			1
Post-modification investment			$ 4.0
Number of notes consolidated into one | customer			12
Contract extension term			28 months
International | Customer one
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers | customer			1
Post-modification investment			$ 3.1
Number of notes consolidated into one | contract			3
Contract extension term			4 months
International | Customer two
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers | customer			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 | customer			1
Number of notes consolidated into one | contract			4
International | Customer three, note one
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-modification investment			$ 1.4
Number of notes consolidated into one | contract			1
Contract extension term			5 months
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 five
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of customers | customer			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 | customer			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 | customer			1
Post-modification investment			$ 0.1
Contract extension term			21 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 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; and •one customer with a note for $0.1 million for which original payment terms were extended by 21 months.