Derivative instruments (Amount and balance sheet location) (Details) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Not designated as hedging instruments | Foreign exchange contracts
Summary of derivatives
Net Notional Exposure		$ 255,602	$ 255,840
Not designated as hedging instruments | Foreign exchange contracts | Other assets
Summary of derivatives
Fair value, derivative assets	[1]	3,122	2,601
Not designated as hedging instruments | Foreign exchange contracts | Accounts payable and accrued expenses
Summary of derivatives
Fair value, derivative liabilities	[1]	1,054	3,211
Not designated as hedging instruments | Interest rate swap contracts
Summary of derivatives
Net Notional Exposure		90,000	0
Not designated as hedging instruments | Interest rate swap contracts | Other assets
Summary of derivatives
Fair value, derivative assets	[1]	566	0
Not designated as hedging instruments | Interest rate swap contracts | Accounts payable and accrued expenses
Summary of derivatives
Fair value, derivative liabilities	[1]	0	0
Designated as hedging instruments | Interest rate swap contracts
Summary of derivatives
Net Notional Exposure		552,263	552,263
Designated as hedging instruments | Interest rate swap contracts | Other assets
Summary of derivatives
Fair value, derivative assets	[2]	20	21
Designated as hedging instruments | Interest rate swap contracts | Accounts payable and accrued expenses
Summary of derivatives
Fair value, derivative liabilities	[2]	$ 2,918	$ 1,942

[1] Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses, respectively, within the Company's consolidated balance sheets.

[2] Asset and liability derivatives are classified within other assets and accounts payable and accrued expenses, respectively, within the Company's consolidated balance sheets.