Basis of Condensed Consolidated Financial Statements (Details) (USD $) In Millions, except Per Share data, unless otherwise specified			6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Minimum [Member]	Jun. 30, 2013 Maximum [Member]	Jun. 30, 2013 Wells Fargo [Member]	Jun. 30, 2012 Wells Fargo [Member]	Jun. 30, 2013 Wells Fargo [Member]	Jun. 30, 2012 Wells Fargo [Member]
Concentration Risk, Customer					.117	.10	.112	.095
Common stock, par value	$ 0.00001	$ 0.00001
Escrow deposit	$ 690.0	$ 228.9
Escrow deposits, period held by the Company (in business days)			2 days	5 days