Fair Value Measurements Fair Value Measurements, Financial Instruments Measured On a Recurring Basis, Quantitative Information (Details) (Fair Value, Inputs, Level 3 [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Municipal and Other Tax-exempt Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Par Value	$ 45,570		$ 46,200
Fair Value Inputs, Asset, Amortized Cost	40,857	[1]	42,492	[1]
Fair Value Inputs, Asset, Fair Value	40,702		42,353
Municipal and Other Tax-exempt Securities [Member] | External Credit Rating, Investment Grade [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Par Value	28,570		29,200
Fair Value Inputs, Asset, Amortized Cost	28,473	[1]	29,466	[1]
Fair Value Inputs, Asset, Fair Value	28,318		29,327
Fair Value Measurements, Valuation Techniques	Discounted cash flows	[2]	Discounted cash flows1	[2]
Fair Value Measurements, Significant Unobservable Input	Interest rate spread		Interest rate spread
Fair Value Inputs, Assets, Discount Rate, Minimum	1.00%	[3]	1.00%	[3]
Fair Value Inputs, Assets, Discount Rate, Maximum	1.50%	[3]	1.50%	[3]
Fair Value Inputs, Assets, Discount Rate, Weighted Average	1.25%	[3]	1.25%	[3]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Minimum	98.83%	[4]	98.79%	[4]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Maximum	99.43%	[4]	99.60%	[4]
Fair Value Inputs, Fair Value As Percentage of Par Value, Weighted Average	99.12%	[4]	99.16%	[4]
Investment Grade Tax Exempt Securities Yield Spread Over Comparable Securities Minimum	75		75
Investment Grade Tax Exempt Securities Yield Spread Over Comparable Securities Maximum	80		80
Additional Decrease in Fair Value From a 100 Basis Point Increase in Interest Rate Spread	(279)
Municipal and Other Tax-exempt Securities [Member] | External Credit Rating, Non Investment Grade [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Par Value	17,000		17,000
Fair Value Inputs, Asset, Amortized Cost	12,384	[1]	13,026	[1]
Fair Value Inputs, Asset, Fair Value	12,384		13,026
Fair Value Measurements, Valuation Techniques	Discounted cash flows	[2]	Discounted cash flows1	[2]
Fair Value Measurements, Significant Unobservable Input	Interest rate spread		Interest rate spread
Fair Value Inputs, Assets, Discount Rate, Minimum	7.21%	[5]	6.25%
Fair Value Inputs, Assets, Discount Rate, Maximum	9.83%	[5]	9.58%
Fair Value Inputs, Assets, Discount Rate, Weighted Average	7.82%	[5]	6.93%
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Minimum	72.79%	[4]	76.45%	[4]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Maximum	73.00%	[4]	76.99%	[4]
Fair Value Inputs, Fair Value As Percentage of Par Value, Weighted Average	72.85%	[4]	76.62%	[4]
Below Investment Grade Tax Exempt Securities Yield Spread Over Comparable Securities	700		600
Additional Decrease in Fair Value From a 100 Basis Point Increase in Interest Rate Spread	(362)
Other Debt Securities [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Par Value	5,400		5,900
Fair Value Inputs, Asset, Amortized Cost	5,400	[1]	5,900	[1]
Fair Value Inputs, Asset, Fair Value	5,399		5,900
Fair Value Measurements, Valuation Techniques	Discounted cash flows	[2]	Discounted cash flows1	[2]
Fair Value Measurements, Significant Unobservable Input	Interest rate spread		Interest rate spread
Fair Value Inputs, Assets, Discount Rate, Minimum	1.65%	[6]	1.60%	[6]
Fair Value Inputs, Assets, Discount Rate, Maximum	1.71%	[6]	1.80%	[6]
Fair Value Inputs, Assets, Discount Rate, Weighted Average	1.70%	[6]	1.76%	[6]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Minimum	100.00%	[4]	100.00%	[4]
Fair Value Inputs, Assets, Fair Value As Percentage of Par Value, Maximum	100.00%	[4]	100.00%	[4]
Fair Value Inputs, Fair Value As Percentage of Par Value, Weighted Average	100.00%	[4]	100.00%	[4]
Average Yields On Comparable Short-term Taxable Securities Maximum	1.00%		1.00%
Additional Decrease in Fair Value From a 100 Basis Point Increase in Interest Rate Spread	(52)
Equity securities and mutual funds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Amortized Cost	2,161
Fair Value Inputs, Asset, Fair Value	2,161
Fair Value Measurements, Valuation Techniques	Tangible book value per share of publicly traded financial institutions of similar size, less liquidity discount.	[2]
Fair Value Measurements, Significant Unobservable Input	Peer group tangible book per share and liquidity discount
Other assets - private equity funds [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value Inputs, Asset, Fair Value	$ 28,169		$ 30,902
Fair Value Measurements, Valuation Techniques	Net asset value reported by underlying fund		Net asset value reported by underlying fund
Fair Value Measurements, Significant Unobservable Input	Net asset value reported by underlying fund		Net asset value reported by underlying fund

[1] Amortized cost reduced by other-than-temporary impairments recorded in earnings. See Note 2 for additional discussion.

[2] Discounted cash flows developed using discount rates primarily based on reference to interest rate spreads for comparable securities of similar duration and credit rating as determined by the nationally-recognized rating agencies, adjusted for lack of trading volume

[3] Interest rate yields used to value investment grade tax-exempt securities represent a spread of 75 to 80 basis points over average yields for comparable tax-exempt securities.

[4] Represents fair value as a percentage of par value

[5] Interest rate yields determined using a spread of 700 basis points over comparable municipal securities of varying durations.

[6] Interest rate yields used to value investment grade taxable securities based on comparable short-term taxable securities which are generally yielding less than 1%.