Fair Value Measurements - Financial Assets and Liabilities, Recurring (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets
Deferred compensation plan	$ 13,566	$ 12,587
Derivative instruments	12,354	2,991
Liabilities
Deferred compensation plan	25,420	24,169
Derivative instruments	12,692	40,259
Recurring basis
Assets
Deferred compensation plan	13,566	12,587
Derivative instruments	10,332	2,991
Total assets	23,898	15,578
Liabilities
Deferred compensation plan	25,420	24,169
Derivative instruments	12,692	40,259
Total liabilities	38,112	64,428
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring basis
Assets
Deferred compensation plan	13,566	12,587
Derivative instruments	0	0
Total assets	13,566	12,587
Liabilities
Deferred compensation plan	25,420	24,169
Derivative instruments	0	0
Total liabilities	25,420	24,169
Significant Other Observable Inputs (Level 2) | Recurring basis
Assets
Deferred compensation plan	0	0
Derivative instruments	0	0
Total assets	0	0
Liabilities
Deferred compensation plan	0	0
Derivative instruments	7,429	21,400
Total liabilities	7,429	21,400
Significant Unobservable Inputs (Level 3) | Recurring basis
Assets
Deferred compensation plan	0	0
Derivative instruments	10,332	2,991
Total assets	10,332	2,991
Liabilities
Deferred compensation plan	0	0
Derivative instruments	5,263	18,859
Total liabilities	$ 5,263	$ 18,859