Summary of Significant Accounting Plicies and Nature of Operations (Details) (USD $)	12 Months Ended						12 Months Ended						0 Months Ended
	Dec. 31, 2012 business_segments	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2012 Granite Corp. [Member]	Dec. 31, 2011 Granite Corp. [Member]	Dec. 31, 2012 Minimum [Member]	Dec. 31, 2012 Minimum [Member] Buildings and Improvements [Member]	Dec. 31, 2012 Minimum [Member] Furniture and Equipment [Member]	Dec. 31, 2012 Maximum [Member]	Dec. 31, 2012 Maximum [Member] Buildings and Improvements [Member]	Dec. 31, 2012 Maximum [Member] Furniture and Equipment [Member]	Dec. 29, 2010 Fannie Mae [Member] CommunityOne [Member]
Nature of Operations [Line Items]
Number of business segments	1
Allowance of loan losses	$ 29,314,000	$ 39,360,000	$ 93,687,000	$ 49,461,000	$ 5,400,000
Accretable yield					20,500,000	4,800,000
Utilization rate on letters of credit	10.00%
Estimated useful lives of assets								10 years	3 years		50 years	10 years
Estimated useful lives of intangible assets							8 years			10 years
Sale of Mortgage Servicing Rights (MSR)													492,900,000
Loss on sale of Mortgage Servicing Rights (MSR)													3,000,000
Other comprehensive loss	(36,359,000)	(137,592,000)	(134,410,000)
Deferred income tax related to the components of other comprehensive loss	200,000	2,600,000
Pension costs	400,000	400,000	600,000
Deferred gain, other comprehensive income	440,000	0	0
Employer matching contribution percentage	50.00%
Percentage of pay deferred by employee eligible for employer matching contributions	6.00%
Matching contributions	600,000	400,000	500,000
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net unrealized securities gains/(losses), Pretax	6,032,000	470,000
Pension, other postretirement and postemployment benefit plan adjustments, Pretax	(6,566,000)	(7,027,000)
Accumulated other comprehensive loss, Pretax	(534,000)	(6,557,000)
Net unrealized securities gains/(losses), After-tax	3,650,000	284,000
Pension, other postretirement and postemployment benefit plan adjustments, After-tax	(3,973,000)	(4,253,000)
Accumulated other comprehensive loss, After-tax	$ (323,000)	$ (3,969,000)