Off-Balance Sheet Guarantees and Long Term Standby Purchase Commitments - Schedule of Guarantee and Commitment Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Loss Contingencies [Line Items]
Term of Guarantees Minimum	1 year
Term of Guarantees Maximum	30 years
Guarantee and commitment obligation	$ 38,609	$ 37,925	$ 39,667	$ 37,803
Additions to the guarantee and commitment obligation(1)	8,207	4,966	8,414
Amortization of the guarantee and commitment obligation	(7,523)	(6,708)	$ (6,550)
Guarantee obligations issued after January 1, 2003 [Member]
Loss Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	4,500,000	3,800,000
Guarantee obligations issued prior to January 1, 2003 [Member]
Loss Contingencies [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 56,200	$ 70,600