Commitments, Contingencies and Guarantees - Employee Retention Plan and Litigation (Details) $ in Thousands, € in Millions	12 Months Ended		36 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jul. 08, 2014 USD ($) installment	Dec. 31, 2015 EUR (€)	Dec. 31, 2015 USD ($)
Employee Retention Plan
Amount which has been paid or will be paid to employees			$ 21,500
Number of installments in which amount has been paid or will be paid to employees | installment			5
Compensation expense	$ 2,639	$ 6,705
Unfavorable regulatory action
Employee Retention Plan
Amount of fine				€ 5.0	$ 5,400
Accrual for estimated loss				€ 5.0	$ 5,400