Fair Value Fair Value Measurements and Disclosures - Financial Instruments Required to be Carried at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Assets:
Government bonds	$ 4,890	$ 5,052
Derivative contracts (recorded in other assets)	2,877	875
Liabilities:
Derivative contracts (recorded in other liabilities)	64,260	23,663
Level 1
Assets:
Derivative contracts (recorded in other assets)	0	0
Liabilities:
Derivative contracts (recorded in other liabilities)	0	0
Level 2
Assets:
Derivative contracts (recorded in other assets)	2,877	875
Liabilities:
Derivative contracts (recorded in other liabilities)	64,260	23,663
Level 3
Assets:
Derivative contracts (recorded in other assets)	0	0
Liabilities:
Derivative contracts (recorded in other liabilities)	0	0
Government bonds
Assets:
Government bonds	4,890	5,052
Government bonds | Level 1
Assets:
Government bonds	4,890	5,052
Government bonds | Level 2
Assets:
Government bonds	0	0
Government bonds | Level 3
Assets:
Government bonds	0	0
Exchange traded funds
Assets:
Mutual funds	19,132	0
Exchange traded funds | Level 1
Assets:
Mutual funds	19,132
Exchange traded funds | Level 2
Assets:
Mutual funds	0
Exchange traded funds | Level 3
Assets:
Mutual funds	0
Mutual funds
Assets:
Mutual funds	639	33,677
Mutual funds | Level 1
Assets:
Mutual funds	639	33,677
Mutual funds | Level 2
Assets:
Mutual funds	0	0
Mutual funds | Level 3
Assets:
Mutual funds	$ 0	$ 0