1. Significant Accounting Policies Immaterial Errors Related to Presentation (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Net Unrealized Holding Gain (Loss) Net Of Income Tax [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	$ 65,448,000	$ 12,663,000
Income Tax On Net Unrealized Holding Gain (Loss) [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	38,108,000	7,373,000
Reclassification Adjustments For Net Holding (Gain) Loss Net Of Income Tax [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	(5,045,000)	104,000
Income Tax on Reclassification Adjustments For Net Holding (Gain) Loss [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	(2,937,000)	61,000
Income Tax on Reclassification Adjustments For Net Holding (Gain) Loss [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	(5,874,000)	121,000
Reclassification Adjustments For Net Holding (Gain) Loss Net Of Income Tax [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	(10,090,000)	208,000
Income Tax On Net Unrealized Holding Gain (Loss) [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	(5,874,000)	121,000
Net Unrealized Holding Gain (Loss) Net Of Income Tax [Member]
Quantifying Misstatement in Current Year Financial Statements [Line Items]
Quantifying Misstatement in Current Year Financial Statements, Amount	$ (10,090,000)	$ 208,000