Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
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Face (par) amount of debt instrument at time of issuance.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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- Definition

The cash inflow from a financial contract that meets the hedge criteria as either cash flow hedge, fair value hedge or hedge of net investment in foreign operations.

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-Publisher FASB
-Name Accounting Standards Codification
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Current period adjustment in other comprehensive income reflecting gains or losses on foreign currency transactions that are designated as, and are effective as, hedges of a net investment in a foreign entity, net of tax effect.

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Derivative Instruments, Hedging Activities and Fair Value (Details 3) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2021	Dec. 31, 2018	Jan. 31, 2017	Dec. 31, 2016
Foreign Currency Derivatives
Pre-tax net gains (losses) on certain loans designated as hedges of net investments in foreign subsidiaries	$ 1,900	$ (3,900)
Proceeds from cross-currency interest rate swap termination	0	16,625
Foreign currency forward exchange contracts
Foreign Currency Derivatives
U.S. Dollar Equivalent	595,472					$ 600,883
Recognized Gain (Loss)	2,601	1,394
Foreign currency forward exchange contracts \| British pounds sterling \| Sell
Foreign Currency Derivatives
U.S. Dollar Equivalent	60,602					55,120
Recognized Gain (Loss)	336	(228)
Foreign currency forward exchange contracts \| British pounds sterling \| Buy
Foreign Currency Derivatives
U.S. Dollar Equivalent	7,287					827
Recognized Gain (Loss)	40	(14)
Foreign currency forward exchange contracts \| Euros \| Sell
Foreign Currency Derivatives
U.S. Dollar Equivalent	306,209					326,797
Recognized Gain (Loss)	1,315	628
Foreign currency forward exchange contracts \| Euros \| Buy
Foreign Currency Derivatives
U.S. Dollar Equivalent	150,326					171,578
Recognized Gain (Loss)	858	(468)
Foreign currency forward exchange contracts \| Other currencies \| Sell
Foreign Currency Derivatives
U.S. Dollar Equivalent	57,635					43,455
Recognized Gain (Loss)	20	1,477
Foreign currency forward exchange contracts \| Other currencies \| Buy
Foreign Currency Derivatives
U.S. Dollar Equivalent	13,413					$ 3,106
Recognized Gain (Loss)	$ 32	$ (1)
Term Loan Facility, Fixed-Rate \| Term Loan
Foreign Currency Derivatives
Principal amount					$ 300,000
LIBOR \| Scenario, Forecast \| Term Loan Facility, Fixed-Rate \| Subsequent Event \| Term Loan
Foreign Currency Derivatives
Debt Instrument, Basis Spread on Variable Rate			2.71%	1.65%