Property Acquisitions (Details) (CPD NY [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
CPD NY [Member]
Summary of Selected Financial Data
Total revenue	$ 222,150	$ 223,049
Gross profit	18,047	17,631
Net income	2,468	3,440
Current assets	6,018		6,166
Noncurrent assets	21,449		20,138
Current liabilities	4,048		1,039
Noncurrent liabilities	$ 14,720		$ 19,033