Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended				12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2012	Aug. 31, 2011	Dec. 31, 2012 Director Plan	Dec. 31, 2012 Purchase Plan	Feb. 23, 2011 Fixed Rate Cumulative Perpetual Preferred Stock Series A	Dec. 31, 2012 Fixed Rate Cumulative Perpetual Preferred Stock Series A
Stockholders Equity Note [Line Items]
Repurchase of outstanding shares of common stock			3.00%
Repurchase of outstanding shares of common stock under Stock Repurchase Program			730,000
Average price repurchased shares of common stock	$ 14.16
Common stock shares authorized	50,000,000	50,000,000
Common stock, par value	$ 1.00	$ 1.00
Shares sold in Purchase Agreement							83,094
Liquidation preference							$ 1,000
Number of securities called by warrants							651,547
Preferred shares annual dividend percentage							5.00%
Exercise price of warrants							19.13
Warrant exercisable term							10 years
Proceeds from issuance of warrants							$ 83,100,000
Value of warrant	24,091,000	24,905,000					3,700,000
Preferred stock discount amortization period							5 years
Redemption of warrant issued						4,500,000
Net reduction of additional paid-in capital						800,000
Shares authorized but unissued				45,000	300,000
Shares available for issuance				26,386	252,740
Share purchase price percentage on fair value					85.00%
Share exercise price description					Shares are purchased at 85% of the fair market value on the exercise date through monthly payroll deductions of not less than 1% or more than 10% of cash compensation paid in the month.
Additional dividend payable		62,600,000
Long term borrowings		$ 35,000,000
Repurchase Of Common Stock Shares	23,592