Estimated Fair Values Estimated Fair Values (Information on Other Real Estate Owned) (Details) (Fair Value, Measurements, Nonrecurring, Fair Value, Inputs, Level 3, USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Covered OREO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current year foreclosures	$ 28,187	$ 28,101	$ 89,817	$ 92,245
Loan charge-offs recorded due to the measurement and initial recognition of OREO	1,965	7,447	10,316	7,447
Write-downs recorded subsequent to forelosure for OREO	2,060	11,431	13,382	15,997
Fair value of OREO remeasured in current period	10,704	7,759	36,972	12,572
Non-covered OREO
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current year foreclosures	8,763	16,590	27,546	30,226
Loan charge-offs recorded due to the measurement and initial recognition of OREO	1,498	1,385	2,086	2,053
Write-downs recorded subsequent to forelosure for OREO	3,074	1,226	6,186	2,910
Fair value of OREO remeasured in current period	$ 6,865	$ 5,813	$ 17,719	$ 12,380