Summary of Significant Accounting Policies - Goodwill Impairment Test (Details) - North America [Member]	12 Months Ended
	Dec. 31, 2015
Market Approach Assumption [Member]
Goodwill Impairment Test [Line Items]
Trailing-twelve months earnings multiple	11.1
Forward earnings multiple	12.7
Weighting applied (percent)	25.00%
Income Approach Assumption [Member]
Goodwill Impairment Test [Line Items]
Weighting applied (percent)	75.00%
Cost of equity (percent)	11.20%
Income Approach Assumption [Member] | Maximum [Member]
Goodwill Impairment Test [Line Items]
Targeted equity-to-earning assets ratio	8.60%
Income Approach Assumption [Member] | Minimum [Member]
Goodwill Impairment Test [Line Items]
Targeted equity-to-earning assets ratio	7.50%
Goodwill [Member]
Goodwill Impairment Test [Line Items]
Percentage of goodwill balance	93.00%