Debt (Components Of Interest Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Debt [Line Items]
Amortization of amendment and arrangement fees	$ 1,764	$ 1,737	$ 2,695
Commitment fees	1,277	1,267	1,937
Sub-total	3,041	3,004	4,632
Interest expense	44,429	41,498	46,819
Other interest expense	1,373	1,595	1,545
York Property Mortgage [Member]
Debt [Line Items]
Interest expense	16,770	16,868	17,007
Senior Notes [Member]
Debt [Line Items]
Interest expense	9,775	6,342	10,049
Convertible Notes [Member]
Debt [Line Items]
Interest expense	$ 13,470	$ 13,689	$ 13,586