Debt (Significant Financial Covenants) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2011
Debt
Minimum consolidated tangible net worth, covenant	$ 800,000
Minimum consolidated tangible net worth	879,382
Ratio of total indebtedness to total asset value, covenant	50.00%
Ratio of total indebtedness to total asset value	3.83%
Unencumbered leverage ratio, covenant	2.0
Unencumbered leverage ratio	71.38
Minimum liquidity, covenant	20,000
Minimum liquidity	$ 324,054