Fair Value Measurements (Narrative) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) property	Jun. 30, 2015 USD ($) property	Dec. 31, 2015 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Percentage of deferred compensation invested in life insurance contracts	65.00%
Number of years long-term sales growth forecasted over	6 years
Average long-term sales growth forecast, over next 4 years, percent per year	14.00%
Combined carrying value	$ 151,250	$ 148,639	$ 150,600
Vacant Owned Facilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Number of vacant owned facilities | property	1	3
Number of properties classified as fixed assets | property	1	2
Estimated combined fair value	$ 3,000	$ 4,000
Combined carrying value	$ 2,500	$ 3,700