Derivatives and Hedging Instruments - Foreign Currency Hedging (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effect of Net Investment Hedge
Currency translation gain (loss)	$ (2,428)	$ (202)	$ 30,174
Net Investment Hedging
Effect of Net Investment Hedge
Currency translation gain (loss)		3,144	(9,375)
Designated as Hedging Instrument \| Foreign Exchange Forward
Gross Notional Amounts and Estimated Fair Values
Gross Notional Amount	495,291	108,680
Assets	642
Liabilities	11,452
Effect of Net Investment Hedge
Amount of Gains (Losses) Deferred in AOCI	(15,328)	4,438	(1,247)
Designated as Hedging Instrument \| Foreign Exchange Forward \| Australia, Dollars
Gross Notional Amounts and Estimated Fair Values
Gross Notional Amount	64,620	42,258
Assets	52	1,377
Liabilities	2,033	0
Effect of Net Investment Hedge
Amount of Gains (Losses) Deferred in AOCI	(722)	3,438	(1,247)
Designated as Hedging Instrument \| Foreign Exchange Forward \| Euro Member Countries, Euro
Gross Notional Amounts and Estimated Fair Values
Gross Notional Amount	112,284	66,422
Assets	246	238
Liabilities	1,635	300
Effect of Net Investment Hedge
Amount of Gains (Losses) Deferred in AOCI	1,817	1,000	0
Designated as Hedging Instrument \| Foreign Exchange Forward \| United Kingdom, Pounds
Gross Notional Amounts and Estimated Fair Values
Gross Notional Amount	318,387	0
Assets	344	0
Liabilities	7,784	0
Effect of Net Investment Hedge
Amount of Gains (Losses) Deferred in AOCI	$ (16,423)	$ 0	$ 0

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