Fair Value Measurements - Assets and Liabilities Measured at Fair Value (Details) - Recurring - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Assets
Mutual funds	$ 117,490	$ 166,330
Derivative financial instruments	5,862	7,509
Total	123,352	173,839
Liabilities
Derivative financial instruments	8,245	3,033
Total	8,245	3,033
Level 1
Assets
Mutual funds	117,490	166,330
Derivative financial instruments	0	0
Total	117,490	166,330
Liabilities
Derivative financial instruments	0	0
Total	0	0
Level 2
Assets
Mutual funds	0	0
Derivative financial instruments	5,862	7,509
Total	5,862	7,509
Liabilities
Derivative financial instruments	8,245	3,033
Total	8,245	3,033
Level 3
Assets
Mutual funds	0	0
Derivative financial instruments	0	0
Total	0	0
Liabilities
Derivative financial instruments	0	0
Total	$ 0	$ 0