Segment Disclosure (Details 1) (USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Reconciliation to Consolidated Net Income:
Total Net Operating Income for segments	$ 65,524	$ 51,033	$ 127,426	$ 99,828
Unallocated (expenses) income:
General and administrative expenses	(7,440)	(6,728)	(14,000)	(13,823)
Acquisition-related expenses	(1,194)	(957)	(1,666)	(1,270)
Depreciation and amortization	(32,248)	(23,722)	(61,559)	(44,660)
Interest income and other net investment gains (losses)	58	(18)	242	366
Interest expense (Note 5)	(21,228)	(13,088)	(42,104)	(25,044)
Loss on early extinguishment of debt		(4,564)		(4,564)
NET INCOME	$ 3,472	$ 1,956	$ 8,339	$ 10,833

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