Income taxes (Narrative) (Details) (USD $)	12 Months Ended						1 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2013	Dec. 31, 2010	Dec. 31, 2008	Sep. 30, 2011 Commercial Loan Purchase Agreement and Residential Loan Purchase Agreement
Income Tax Disclosure [Abstract]
Income Tax Expense (Benefit)	$ (50,146,000)	$ 79,000	$ (11,721,000)
Valuation allowance for deferred tax assets	(74,000)	(41,698,000)		(41,600,000)
Previously Written Off Section 382 Deferred Tax Benefits	8,500,000
Provision (credit) for income taxes	50,146,000	(79,000)	(10,372,000)
Extinguishment of Debt, Gain (Loss), Income Tax			22,100,000
Gains (Losses) on Extinguishment of Debt			11,800,000
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	27,400,000	15,600,000
Deferred Tax Assets, Charitable Contribution Carryforwards	700,000	900,000
Deferred Tax Assets Federal Tax Credits Forwards	1,000,000	400,000
Deferred Tax Assets, Operating Loss Carryforwards, State and Local	5,700,000	3,900,000
Deferred Tax Assets State Tax Credits Forwards	100,000	200,000
Income (loss) before income taxes and extraordinary net gain	699,000	6,030,000	(91,836,000)
Other Real Estate Valuation Adjustments For Specific Properties			5,000,000
Non Owner Occupied Commercial Real Estate as a Percentage of Regulatory Capital	255.00%				720.00%
Acquisition Development and Construction Loans as a Percentage of Regulatory Capital	34.00%					293.00%
Percentage Change in Classified Assets	81.00%
Income Taxes Paid	100,000	100,000	800,000
Proceeds from Income Tax Refunds	100,000	0
Capital Raise and Bulk Sale of Distressed Assets [Line Items]
Allowance for Loan and Lease Losses, Write-offs			81,400,000				54,000,000
Loans and Leases Receivable, Gross	$ 996,232,000	$ 858,164,000					$ 110,000,000