Goodwill and Other Intangibles (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Increase (decrease) in goodwill	$ 0		$ 200,000
Goodwill impairment	0		0
Amortization expense of amortizable intangible assets	1,200,000	1,700,000	3,800,000	4,700,000
Favorable Leases [Member]
Weighted-average remaining useful life of favorable leases, in years			10 years 0 months 28 days
Unfavorable Leases [Member]
Weighted-average remaining useful life of unfavorable leases, in years			5 years 5 months 8 days
Amortization benefit of unfavorable operating leases	$ 1,400,000	$ 1,800,000	$ 4,300,000	$ 5,100,000