Fair Value Measurements - Financial Assets and Liabilities, Recurring (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets
Deferred compensation plan	$ 12,297	$ 12,921
Derivative instruments	2,668	0
Liabilities
Deferred compensation plan	25,088	22,371
Derivative instruments	6,153	0
Recurring basis
Assets
Deferred compensation plan	12,297	12,921
Derivative instruments	1,662
Total assets	13,959	12,921
Liabilities
Deferred compensation plan	25,088	22,371
Derivative instruments	6,153
Total liabilities	31,241	22,371
Quoted Prices in Active Markets for Identical Assets (Level 1) | Recurring basis
Assets
Deferred compensation plan	12,297	12,921
Derivative instruments	0
Total assets	12,297	12,921
Liabilities
Deferred compensation plan	25,088	22,371
Derivative instruments	0
Total liabilities	25,088	22,371
Significant Other Observable Inputs (Level 2) | Recurring basis
Assets
Deferred compensation plan	0	0
Derivative instruments	(233)
Total assets	(233)	0
Liabilities
Deferred compensation plan	0	0
Derivative instruments	4,722
Total liabilities	4,722	0
Significant Unobservable Inputs (Level 3) | Recurring basis
Assets
Deferred compensation plan	0	0
Derivative instruments	1,895
Total assets	1,895	0
Liabilities
Deferred compensation plan	0	0
Derivative instruments	1,431
Total liabilities	$ 1,431	$ 0