Goodwill and Other Intangibles (Amortizable Intangibles) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Amortizable Intangibles
Amortizable intangible assets, cost	$ 24,351	$ 29,847
Amortizable intangible assets, accumulated amortization expense	(14,959)	(18,518)
Net amortizable intangible assets	9,392	11,329
Favorable Leases [Member]
Amortizable Intangibles
Amortizable intangible assets, cost	22,500	27,960
Amortizable intangible assets, accumulated amortization expense	(14,495)	(18,104)
Net amortizable intangible assets	8,005	9,856
Non-compete Agreements [Member]
Amortizable Intangibles
Amortizable intangible assets, cost	1,851	1,887
Amortizable intangible assets, accumulated amortization expense	(464)	(414)
Net amortizable intangible assets	1,387	1,473
Unfavorable Leases [Member]
Amortizable Intangibles
Amortizable intangibles, cost	14,470	19,950
Amortizable intangibles, accumulated amortization benefit	11,853	15,840
Net amortizable intangibles	$ 2,617	$ 4,110