Loans (Details 8) (Residential mortgage Loans [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	$ 1,507,498	$ 659,689
Pass [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	1,254,192	444,597
Pass-Watch [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	27,405	37,530
Special Mention [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	13,514	15,220
Substandard [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	207,069	161,251
Doubtful [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	5,318	1,091
Loss [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	0	0
Originated loans [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	487,147	366,184
Originated loans [Member] | Pass [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	460,261	284,712
Originated loans [Member] | Pass-Watch [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	7,499	7,857
Originated loans [Member] | Special Mention [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	542	0
Originated loans [Member] | Substandard [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	18,845	73,615
Originated loans [Member] | Doubtful [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	0	0
Originated loans [Member] | Loss [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	0	0
Acquired loans [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	734,669
Acquired loans [Member] | Pass [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	673,751
Acquired loans [Member] | Pass-Watch [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	1,773
Acquired loans [Member] | Special Mention [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	9,686
Acquired loans [Member] | Substandard [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	48,581
Acquired loans [Member] | Doubtful [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	878
Acquired loans [Member] | Loss [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	0
Covered loans [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	285,682	293,505
Covered loans [Member] | Pass [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	120,180	159,885
Covered loans [Member] | Pass-Watch [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	18,133	29,673
Covered loans [Member] | Special Mention [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	3,286	15,220
Covered loans [Member] | Substandard [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	139,643	87,636
Covered loans [Member] | Doubtful [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	4,440	1,091
Covered loans [Member] | Loss [Member]
Residential Mortgage Credit Exposure
Credit risk profile by internally assigned grade	$ 0	$ 0