Fair Value Measurement (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets and liabilities measured at fair value
Deferred compensation investments	$ 77,880	$ 77,199
Available for sale investment	23,815	28,090
Total	101,695	105,289
Level 1
Assets and liabilities measured at fair value
Deferred compensation investments	77,880	77,199
Available for sale investment	23,815	28,090
Total	101,695	105,289
Level 2
Assets and liabilities measured at fair value
Deferred compensation investments	0	0
Available for sale investment	0	0
Total	0	0
Level 3
Assets and liabilities measured at fair value
Deferred compensation investments	0	0
Available for sale investment	0	0
Total	$ 0	$ 0