Fair Value Measurement - Narrative (Details)	3 Months Ended
	Mar. 31, 2016 USD ($) forward_exchange_contrtact	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	$ 56,600,000		$ 52,000,000
Trading securities	9,700,000		9,700,000
Purchase of trading securities related to deferred compensation plans	900,000	$ 800,000
Proceeds from securities sold	$ 1,100,000	$ 200,000
Number of foreign exchange contracts held (foreign_exchange_contract) | forward_exchange_contrtact	48
Derivative, notional amount	$ 52,400,000.0
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	0		0
Trading securities	9,700,000		9,700,000
Quoted Prices in Active Markets for Similar Assets (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	51,700,000		47,400,000
Trading securities	0		0
Unobservable inputs for which little or no market data exists (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale investments	4,900,000		4,600,000
Trading securities	$ 0		$ 0