Covered Assets and FDIC Indemnification Asset (Internal Risk Rating by Loan Class) (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Commercial real estate, Term & multifamily	$ 3,532,134,000	$ 3,483,475,000
Commercial real estate, Construction & development	184,707,000	247,814,000
Commercial real estate, Residential development	112,657,000	147,813,000
Commercial, Term	572,402,000	509,453,000
Commercial, LOC & other	788,268,000	747,419,000
Residential, Mortgage	245,034,000	222,416,000
Residential, Home equity loans & lines	277,453,000	278,585,000
Consumer & other	34,584,000	33,043,000
Total	5,747,239,000	5,670,018,000
Covered Loans [Member]
Commercial real estate, Term & multifamily	515,949,000.000	569,642,000.000
Commercial real estate, Construction & development	19,818,000.000	22,435,000.000
Commercial real estate, Residential development	15,947,000.000	24,706,000.000
Commercial, Term	37,251,000.000	42,600,000.000
Commercial, LOC & other	28,480,000.000	35,227,000.000
Residential, Mortgage	41,068,000.000	44,824,000.000
Residential, Home equity loans & lines	31,454,000.000	35,625,000.000
Consumer & other	8,709,000.000	10,839,000.000
Total	698,676,000.000	785,898,000.000
Covered Loans [Member] | Pass/Watch [Member]
Commercial real estate, Term & multifamily	419,493,000.000	485,238,000.000
Commercial real estate, Construction & development	3,060,000.000	6,155,000.000
Commercial real estate, Residential development	1,646,000.000	6,625,000.000
Commercial, Term	24,285,000.000	31,760,000.000
Commercial, LOC & other	19,506,000.000	22,960,000.000
Residential, Mortgage	41,051,000.000	44,524,000.000
Residential, Home equity loans & lines	31,393,000.000	34,998,000.000
Consumer & other	8,709,000.000	10,827,000.000
Total	549,143,000.000	643,087,000.000
Covered Loans [Member] | Special Mention [Member]
Commercial real estate, Term & multifamily	38,176,000.000	32,150,000.000
Commercial real estate, Construction & development	2,919,000.000	3,799,000.000
Commercial real estate, Residential development		1,322,000.000
Commercial, Term	1,970,000.000	2,119,000.000
Commercial, LOC & other	1,953,000.000	4,246,000.000
Total	45,018,000.000	43,636,000.000
Covered Loans [Member] | Substandard [Member]
Commercial real estate, Term & multifamily	47,689,000.000	44,833,000.000
Commercial real estate, Construction & development	8,489,000.000	7,640,000.000
Commercial real estate, Residential development	9,012,000.000	12,907,000.000
Commercial, Term	8,385,000.000	7,087,000.000
Commercial, LOC & other	6,720,000.000	7,183,000.000
Residential, Mortgage	17,000.000	300,000.000
Residential, Home equity loans & lines	61,000.000	627,000.000
Consumer & other		12,000.000
Total	80,373,000.000	80,589,000.000
Covered Loans [Member] | Doubtful/Loss [Member]
Commercial real estate, Term & multifamily	10,591,000.000	7,421,000.000
Commercial real estate, Construction & development	5,350,000.000	4,841,000.000
Commercial real estate, Residential development	5,289,000.000	3,852,000.000
Commercial, Term	2,611,000.000	1,634,000.000
Commercial, LOC & other	301,000.000	838,000.000
Total	$ 24,142,000.000	$ 18,586,000.000