Loans (Details) (Real estate - mortgage, 1-4 family residential [Member], PC [Member], Granite Corp [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Real estate - mortgage, 1-4 family residential [Member] | PC [Member] | Granite Corp [Member]
Financing Receivable [Line Items]
Loans purchases	$ 119.0	$ 137.4
Loans purchases premium	$ 1.6	$ 3.7