Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Level 1
Assets (Liabilities) at fair value
Non-qualified deferred compensation assets	$ 73,065	$ 77,228
Non-qualified deferred compensation liabilities	(72,869)	(76,255)
Level 2
Assets (Liabilities) at fair value
Interest rate swap	(5,085)
Acquisition-related deferred consideration	(53,999)	(53,933)
Level 3
Assets (Liabilities) at fair value
Acquisition-related contingent consideration and compensation liabilities	(7,461)	$ (13,218)
Payment Acquisition-related contingent consideration and compensation liabilities	0
Level 3 | Minimum
Assets (Liabilities) at fair value
Undiscounted range of out comes	0
Level 3 | Maximum
Assets (Liabilities) at fair value
Undiscounted range of out comes	$ 35,600