Fair Value Measurements - Assets and Liabilities on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets
Deferred compensation plan	$ 12,587	$ 12,921
Derivative instruments	2,991	0
Total assets	15,578	12,921
Liabilities
Deferred compensation plan	24,169	22,371
Derivative instruments	40,259	0
Total liabilities	64,428	22,371
Recurring Basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Deferred compensation plan	12,587	12,921
Derivative instruments	0
Total assets	12,587	12,921
Liabilities
Deferred compensation plan	24,169	22,371
Derivative instruments	0
Total liabilities	24,169	22,371
Recurring Basis | Significant Other Observable Inputs (Level 2)
Assets
Deferred compensation plan	0	0
Derivative instruments	0
Total assets	0	0
Liabilities
Deferred compensation plan	0	0
Derivative instruments	21,400
Total liabilities	21,400	0
Recurring Basis | Significant Unobservable Inputs (Level 3)
Assets
Deferred compensation plan	0	0
Derivative instruments	2,991
Total assets	2,991	0
Liabilities
Deferred compensation plan	0	0
Derivative instruments	18,859
Total liabilities	$ 18,859	$ 0