Bank Regulatory Capital (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2011	Dec. 31, 2010
Capital ratios and the minimum requirements
Tier-1 Leverage, Actual	$ 820,788	$ 756,821
Tier-1 Leverage, Actual - Ratio	13.47%	13.15%
Tier-1 Leverage, Minimum Required	304,639	287,830
Tier-1 Leverage, Minimum Required - Ratio	5.00%	5.00%
Tier-1 Risk-Based Capital, Actual	820,788	756,821
Tier-1 Risk-Based Capital, Actual - Ratio	17.40%	16.86%
Tier-1 Risk-Based Capital, Minimum Required	282,979	269,335
Tier-1 Risk-Based Capital, Minimum Required - Ratio	6.00%	6.00%
Total Risk-Based Capital, Actual	880,378	813,822
Total Risk-Based Capital, Actual - Ratio	18.67%	18.13%
Total Risk-Based Capital, Minimum Required	$ 707,448	$ 673,336
Total Risk-Based Capital, Minimum Required - Ratio	15.00%	15.00%

Capital ratios and the minimum requirements.

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Tier 1 Risk Based Capital as defined in the regulations.

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