Loans (Details 6) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Summary of Age Analysis of Past Due Loans
30-89 days past due	$ 53,599	$ 41,071
Greater than 90 days past due	109,150	122,477
Total past due	162,749	163,548
Current	11,014,277	4,793,616
Total Loans	11,177,026	4,957,164
Recorded investment > 90 days and accruing	5,880	1,492
Originated loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	51,471	41,071
Greater than 90 days past due	88,178	77,191
Total past due	139,649	118,262
Current	4,748,081	4,029,751
Total Loans	4,887,730	4,148,013
Recorded investment > 90 days and accruing	4,871	1,492
Acquired loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	2,128	0
Greater than 90 days past due	2,126	0
Total past due	4,254	0
Current	5,613,599	0
Total Loans	5,617,853	0
Recorded investment > 90 days and accruing	1,009	0
Covered loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	0	0
Greater than 90 days past due	18,846	45,286
Total past due	18,846	45,286
Current	652,597	763,865
Total Loans	671,443	809,151
Recorded investment > 90 days and accruing	0	0
Commercial Loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	24,939	12,463
Greater than 90 days past due	77,076	92,596
Total past due	102,015	105,059
Current	7,960,143	3,042,706
Total Loans	8,062,158	3,147,765
Recorded investment > 90 days and accruing	3,821	300
Commercial Loans [Member] | Originated loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	24,939	12,463
Greater than 90 days past due	58,867	50,679
Total past due	83,806	63,142
Current	3,242,166	2,710,292
Total Loans	3,325,972	2,773,434
Recorded investment > 90 days and accruing	3,821	300
Commercial Loans [Member] | Acquired loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	0	0
Greater than 90 days past due	0	0
Total past due	0	0
Current	4,496,644	0
Total Loans	4,496,644	0
Recorded investment > 90 days and accruing	0	0
Commercial Loans [Member] | Covered loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	0	0
Greater than 90 days past due	18,209	41,917
Total past due	18,209	41,917
Current	221,333	332,414
Total Loans	239,542	374,331
Recorded investment > 90 days and accruing	0	0
Residential mortgage Loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	22,248	22,109
Greater than 90 days past due	26,037	22,772
Total past due	48,285	44,881
Current	1,459,213	614,808
Total Loans	1,507,498	659,689
Recorded investment > 90 days and accruing	994	874
Residential mortgage Loans [Member] | Originated loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	22,248	22,109
Greater than 90 days past due	25,400	19,573
Total past due	47,648	41,682
Current	439,499	324,502
Total Loans	487,147	366,184
Recorded investment > 90 days and accruing	994	874
Residential mortgage Loans [Member] | Acquired loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	0	0
Greater than 90 days past due	0	0
Total past due	0	0
Current	734,669	0
Total Loans	734,669	0
Recorded investment > 90 days and accruing	0	0
Residential mortgage Loans [Member] | Covered loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	0	0
Greater than 90 days past due	637	3,199
Total past due	637	3,199
Current	285,045	290,306
Total Loans	285,682	293,505
Recorded investment > 90 days and accruing	0	0
Consumer loan [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	6,412	6,499
Greater than 90 days past due	6,037	7,109
Total past due	12,449	13,608
Current	1,594,921	1,136,102
Total Loans	1,607,370	1,149,710
Recorded investment > 90 days and accruing	1,065	318
Consumer loan [Member] | Originated loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	4,284	6,499
Greater than 90 days past due	3,911	6,939
Total past due	8,195	13,438
Current	1,066,416	994,957
Total Loans	1,074,611	1,008,395
Recorded investment > 90 days and accruing	56	318
Consumer loan [Member] | Acquired loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	2,128	0
Greater than 90 days past due	2,126	0
Total past due	4,254	0
Current	382,286	0
Total Loans	386,540	0
Recorded investment > 90 days and accruing	1,009	0
Consumer loan [Member] | Covered loans [Member]
Summary of Age Analysis of Past Due Loans
30-89 days past due	0	0
Greater than 90 days past due	0	170
Total past due	0	170
Current	146,219	141,145
Total Loans	146,219	141,315
Recorded investment > 90 days and accruing	$ 0	$ 0