Computation of Basic and Diluted Earnings per Common Share - Summary of Computation of Basic and Diluted Earnings per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings per common share
Net income attributable to SCUSA	$ 81,466	$ 290,402
Weighted average number of common shares outstanding before restricted participating shares	347,517,891	346,164,763
Weighted average number of participating restricted common shares outstanding	584,000
Weighted average number of common shares outstanding	348,101,891	346,164,763
Earnings per common share	$ 0.23	$ 0.84
Earnings per common share - assuming dilution
Net income attributable to SCUSA	$ 81,466	$ 290,402
Weighted average common shares (basic)	348,101,891	346,164,763
Effect of employee stock-based awards	8,223,000
Weighted average number of common shares outstanding - assuming dilution	356,325,036	346,164,763
Earnings per common share - assuming dilution	$ 0.23	$ 0.84