Debt (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended			3 Months Ended
	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2015	Mar. 31, 2015	Jul. 23, 2014	Sep. 08, 2014	Jun. 01, 2015	Feb. 02, 2015
Debt Instrument
Long-term debt principal total		$ 1,826,239,000
Long-term debt, maturities, repayments of principal, 2015		238,000,000
Long-term debt, maturities, repayments of principal, 2016		465,200,000
Long-term debt, maturities, repayments of principal, 2017		123,000,000
Long-term debt, maturities, repayments of principal, 2018		0
Long-term debt, maturities, repayments of principal, 2019		0
Long-term debt, maturities, repayments of principal, thereafter		1,000,000,000
Extinguishment of debt, amount		245,700,000	461,400,000	592,400,000
Loss on debt retirements	8,584,000	8,584,000	26,930,000	32,071,000
Letters of credit outstanding, amount		212,100,000	183,100,000
Notes Payable		22,255,000	7,521,000
Debt Instrument, Term		6 years
Financial Services debt		140,241,000	105,664,000
Maximum [Member]
Debt Instrument
Debt instrument, interest rate, stated percentage		5.00%
Unsecured Letter Of Credit Facility [Member]
Debt Instrument
Letters of credit outstanding, amount		208,400,000
Letter Of Credit [Member]
Debt Instrument
Letters of credit outstanding, amount		3,700,000	58,700,000
Revolving Credit Facility [Member]
Debt Instrument
Maximum borrowing capacity							500,000,000
Line of Credit, Current		0
Line of Credit Facility, Initiation Date		Jul. 23, 2014
Line of Credit Facility, Expiration Date		Jul. 21, 2017
Revolving Credit Facility Accordion Feature [Member]
Debt Instrument
Maximum borrowing capacity							1,000,000,000
Financial Services [Member]
Debt Instrument
Maximum borrowing capacity		150,000,000	150,000,000	150,000,000
Financial Services [Member] | Unsecured Letter Of Credit Facility [Member]
Debt Instrument
Line of Credit Facility, Expiration Date		Sep. 01, 2014
Financial Services [Member] | Repurchase Agreement [Member]
Debt Instrument
Maximum borrowing capacity								150,000,000
Line of Credit Facility, Initiation Date		Sep. 08, 2014
Line of Credit Facility, Expiration Date		Sep. 07, 2015
Financial Services debt		140,200,000	105,700,000
Financial Services [Member] | Repurchase Agreement [Member] | Scenario, Forecast [Member]
Debt Instrument
Maximum borrowing capacity									$ 150,000,000	$ 99,800,000
Line of Credit Facility, Initiation Date					Jun. 01, 2015	Feb. 02, 2015