Loans and reserve for credit losses (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended						6 Months Ended		6 Months Ended								6 Months Ended												6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jun. 30, 2014 Troubled Debt Restructuring	Dec. 31, 2013 Troubled Debt Restructuring	Jun. 30, 2013 Troubled Debt Restructuring	Jun. 30, 2014 Unallocated Financing Receivables	Dec. 31, 2013 Unallocated Financing Receivables	Jun. 30, 2014 Originated Loans		Dec. 31, 2013 Originated Loans		Jun. 30, 2014 Acquired Loans		Jun. 30, 2014 Acquired Covered Loans		Jun. 30, 2014 Acquired and Acquired Covered Loans		Jun. 30, 2014 Substandard	Dec. 31, 2013 Substandard	Jun. 30, 2014 Substandard Originated Loans		Jun. 30, 2014 Substandard Acquired Loans		May 16, 2014 Substandard Acquired Loans		May 16, 2014 Substandard Acquired Covered Loans		Jun. 30, 2014 Loan Receivables Acquired and Acquired Covered Loans
Financing Receivable, Impaired [Line Items]
Percentage Of Real Estate Related Loans	75.70%		75.70%								70.10%
Loans participated to third-parties	$ 29,900,000		$ 29,900,000		$ 11,300,000
Assets, Fair Value Adjustment																			6,100,000
Life of the loans																															10 years
Loans and Leases Receivable, Gross	1,394,928,000		1,394,928,000		996,232,000						1,016,658,000	[1]	996,232,000	[1]	324,670,000	[2],[3]	53,600,000	[4],[5]	378,270,000	[4]	53,160,000	41,194,000	35,497,000	[1]	9,345,000	[3]	17,663,000	[4]	8,318,000	[4]
Percentage of Acquired Loans Covered	14.20%		14.20%
Loans And Leases Receivable Gross, Percent	100.00%		100.00%								100.00%	[1]	100.00%	[1]	100.00%	[3]	100.00%	[4]									4.70%		47.10%
Loss Sharing Agreement, Expiration Period, Single Family Covered Assets			10 years
Loss Sharing Agreement, Covered Assets, Risk-Weighting Percent During Agreement Period			20.00%
Loss Sharing Agreement, Covered Assets, Potential Risk-Weighting Percent After Expiration			100.00%
Loss Sharing Agreement, Expiration Period, Non-Single Family Covered Assets			5 years
Loan loss provision	0	1,000,000	0	1,000,000					800,000
Loans and Leases Receivable, Allowance	20,471,000		20,471,000		20,857,000	200,000	800,000		1,919,000	714,000	20,471,000	[1]	20,857,000	[1]	0	[3]	0	[4]
Reductions in Loans Classified as Special Mention and Substandard			17,500,000								(14,600,000)
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	790,000		790,000		1,083,000
Impaired loans, Total recorded balance	33,861,000		33,861,000		40,467,000	23,000,000	33,200,000
Remaining Commitment To Lend Loan						$ 0		$ 0

[1] Originated loans are loans organically made through the Company's normal and customary origination process

[2] Acquired loans are loans acquired in the acquisition of Home, discussed elsewhere in this report, less acquired covered loans

[3] Acquired loans are loans acquired in the acquisition of Home, discussed elsewhere in this report

[4] Acquired covered loans are loans in the Home portfolio that are covered under FDIC loss share agreements

[5] Acquired covered loans acquired in the acquisition of Home that are covered under FDIC loss share agreements