Fair Value Measurements (Details) (Fair Value, Measurements, Recurring [Member], USD $)	Jun. 30, 2012	Dec. 31, 2011
Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	$ 30,013,000	$ 10,002,000
Total Assets	30,013,000	10,002,000
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	0	0
Total Liabilities	0	0
Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	9,563,000	11,541,000
Total Assets	9,563,000	11,541,000
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	(4,362,000)	(5,024,000)
Total Liabilities	(4,362,000)	(5,024,000)
Difference between fair value and carrying value, debt	6,200,000
Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	0	0
Total Assets	0	0
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	0	0
Total Liabilities	0	0
Total [Member]
Assets, Fair Value Disclosure [Abstract]
Cash equivalents - money market	39,576,000	21,543,000
Total Assets	39,576,000	21,543,000
Liabilities, Fair Value Disclosure [Abstract]
Interest rate swap	(4,362,000)	(5,024,000)
Total Liabilities	(4,362,000)	(5,024,000)
Carrying (Reported) Amount, Fair Value Disclosure [Member]
Liabilities, Fair Value Disclosure [Abstract]
Carrying value, debt	$ 363,200,000