Leasing (Net Rent Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leases, Rent Expense, Net [Abstract]
Minimum operating lease expense	$ 273,559	$ 263,479	$ 254,565
Contingent rents	892	947	759
Other lease related occupancy costs	13,241	12,852	11,688
Total rent expense	287,692	277,278	267,012
Less: sublease income	4,439	4,019	3,984
Net rent expense	$ 283,253	$ 273,259	$ 263,028