Indebtedness - Senior Debt Prior Term Loan (Details)			12 Months Ended
	Dec. 19, 2017 USD ($)	Sep. 01, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Loss on amendment/refinancing of senior credit agreement			$ 900,000	$ 1,300,000	$ 1,400,000
Term loans | Senior Credit Facilities | Alternative base rate
Debt Instrument [Line Items]
Description of variable rate (as a percent)		alternate base rate
Term loans | Senior Credit Facilities | Federal Funds Effective Swap Rate
Debt Instrument [Line Items]
Description of variable rate (as a percent)		federal funds effective rate
Basis spread on variable rate (as a percent)		0.50%
Term loans | Senior Credit Facilities | Prime Rate
Debt Instrument [Line Items]
Description of variable rate (as a percent)		prime rate
Term loans | Senior Credit Facilities | One-Month LIBOR
Debt Instrument [Line Items]
Description of variable rate (as a percent)		one-month LIBOR
Basis spread on variable rate (as a percent)		1.00%
Term loans | Senior Credit Facilities | Reserve adjusted LIBOR
Debt Instrument [Line Items]
Description of variable rate (as a percent)		reserve-adjusted LIBOR
Term loans | Senior Credit Facilities | London Interbank Offered Rate (LIBOR), Period One
Debt Instrument [Line Items]
Interest period which may be elected, shortest		1 month
Term loans | Senior Credit Facilities | London Interbank Offered Rate (LIBOR), Period Two
Debt Instrument [Line Items]
Interest period which may be elected, shortest		2 months
Term loans | Senior Credit Facilities | London Interbank Offered Rate (LIBOR), Period Three
Debt Instrument [Line Items]
Interest period which may be elected, shortest		3 months
Term loans | Senior Credit Facilities | London Interbank Offered Rate (LIBOR), Period Four
Debt Instrument [Line Items]
Interest period which may be elected, shortest		6 months
Term loans | Purchase Card Program
Debt Instrument [Line Items]
Amount outstanding under purchase card programs			$ 2,800,000	$ 3,900,000
Senior credit facility | Senior Credit Facilities
Debt Instrument [Line Items]
Weighted-average interest rate of senior credit facilities (as a percent)			3.20%
Maximum period within which net proceeds should be reinvested		360 days
Period after end of 360 day period if committed to be reinvested		180 days
Percentage of capital stock		100.00%
Percentage of capital stock of material first tier foreign subsidiaries		65.00%
Consolidated interest coverage ratio		3.50
Consolidated leverage ratio	3.50	3.50
Consolidated leverage ratio after certain permitted acquisitions	4.00	4.00
Consolidated leverage ratio to repurchase capital stock and pay cash dividends		2.75
Aggregate amount of repurchases and dividend declarations		$ 50,000,000.0
Additional amount for all such repurchases and dividend declarations after effective date		$ 100,000,000
Percentage of cumulative consolidated net income		50.00%
Percentage of cumulative consolidated net deficit		100.00%
Maximum borrowing capacity under financing arrangement	$ 900,000,000.0
Domestic revolving credit facility
Debt Instrument [Line Items]
Amount of available borrowing capacity			$ 314,300,000
Letters of credit issued, amount outstanding			35,700,000
Maximum borrowing capacity under financing arrangement	200,000,000.0
Letters of credit and guarantees | Senior Credit Facilities
Debt Instrument [Line Items]
Fronting fees percentage		0.125%
Foreign credit instrument facility
Debt Instrument [Line Items]
Amount of available borrowing capacity			16,900,000
Letters of credit issued, amount outstanding			183,100,000
Maximum borrowing capacity under financing arrangement	$ 150,000,000.0
Foreign credit instrument facility | Senior Credit Facilities
Debt Instrument [Line Items]
Fronting fees percentage		0.25%
Trade receivables financing arrangement
Debt Instrument [Line Items]
Maximum borrowing capacity under financing arrangement			50,000,000.0
China, India, and South Africa | Foreign credit instrument facility
Debt Instrument [Line Items]
Maximum borrowing capacity under financing arrangement			20,200,000.0
Foreign line of credit			$ 4,200,000