Commitments and Contingent Liabilities Guarantor Obligations (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Guarantor Obligations [Line Items]
Purchase price of tax credits	$ 13
Property Lease Guarantee [Member]
Guarantor Obligations [Line Items]
Total amount of guaranteed rents	28.7
Contingent Obligation For Guaranteed Rents	11.2
Guaranteed Percentage To Be Received (in hundredths)	80.00%
Maximum Amount To Be Received Under Rent Agreement With City Of Tulsa	4.5
BOSC, Inc. [Member]
Guarantor Obligations [Line Items]
Customer balances subject to indemnification by Pershing, LLC	$ 1.4