Parent company financial information (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Cash flows from operating activities:
Net income (loss)	$ 5,951		$ (47,276)		$ (13,655)
Adjustments to reconcile net loss to net cash providedby (used in) operating activities:
Stock-based compensation expense	1,050		649		846
Net cash provided by operating activities before extraordinary net gain	7,684		43,518		63,902
Extraordinary gain on extinguishment of junior subordinated debentures, net of tax	0		32,839		0
Net cash provided by operating activities	7,684		10,679		63,902
Cash flows from financing activities:
Tax effect of nonvested restricted stock	(82)		17		(147)
Proceeds from issuance of common stock	0		168,074		0
Extinguishment of junior subordinated debentures, net	0		(13,625)		0
Net cash used by financing activities	(10,675)		(311,606)		(438,803)
Net increase (decrease) in cash and cash equivalents	(15,411)		(142,825)		(88,058)
Cash and cash equivalents at beginning of year	128,439		271,264		359,322
Cash and cash equivalents at end of year	113,028		128,439		271,264
Parent Company [Member]
Cash flows from operating activities:
Net income (loss)	5,951		(47,276)		(13,655)
Adjustments to reconcile net loss to net cash providedby (used in) operating activities:
Equity in undistributed net losses of subsidiary	(7,297)		101,023		9,972
Tax benefit from consolidated tax return	0		(22,094)		0
Stock-based compensation expense	1,050		649		846
Increase in other assets	(6)		(7)		(5)
(Decrease) increase in other liabilities	(9)		(5,410)		669
Net cash provided by operating activities before extraordinary net gain	(311)		26,885		(2,173)
Extraordinary gain on extinguishment of junior subordinated debentures, net of tax	0		32,840		0
Net cash provided by operating activities	(311)		(5,955)		(2,173)
Cash flows from investing activities:
Proceeds from sales of investment securities available-for-sale Investment in subsidiary	0		(150,400)		0
Cash flows from financing activities:
Tax effect of nonvested restricted stock	(82)		17		(147)
Proceeds from issuance of common stock	0		168,074		0
Extinguishment of junior subordinated debentures, net	0		(11,567)		0
Net cash used by financing activities	(82)		156,524		(147)
Net increase (decrease) in cash and cash equivalents	(393)		169		(2,320)
Cash and cash equivalents at beginning of year	512	[1]	343		2,663
Cash and cash equivalents at end of year	$ 119		$ 512	[1]	$ 343

[1] Adjusted to correct an error in the computation of the Bank's regulatory capital at December 31, 2011. See Note 16 to the Company's condensed consolidated financial statements included in the Company's Quarterly Report on Form 10-Q for the quarter ended June 30, 2012.