Debt (Schedule of Debt) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Debt Instrument [Line Items]
Revolving credit facility - unsecured	$ 107,500,000us-gaap_LineOfCredit	$ 374,000,000us-gaap_LineOfCredit
Convertible Debt	193,308,000us-gaap_ConvertibleDebt	193,037,000us-gaap_ConvertibleDebt	192,238,000us-gaap_ConvertibleDebt
Bank term loans - unsecured	250,000,000us-gaap_UnsecuredDebt	250,000,000us-gaap_UnsecuredDebt
Debt, Long-term and Short-term, Combined Amount	899,420,000	862,726,000
Debt Instrument, Name, HUD Mortgages [Member]
Debt Instrument [Line Items]
Secured Debt	45,528,000	45,689,000
Private Placement Term Loans [Member]
Debt Instrument [Line Items]
Bank term loans - unsecured	225,000,000	0
Debt Instrument, Name, Fannie Mae Term Loans [Member]
Debt Instrument [Line Items]
Secured Debt	$ 78,084,000	$ 0

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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