Loans (Details) (USD $)	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Mortgage loans on real estate:
Total mortgage loan on real estate	$ 1,010,249,000	$ 1,010,130,000
Consumer:
Total consumer loans	376,063,000	386,111,000
Commercial	115,483,000	135,528,000
Construction:
Total construction	30,567,000	33,054,000
Total loans, net of deferred loan fees	1,532,362,000	1,564,823,000
Total principal balance of loans owed-net of charge-offs	1,573,092,000	1,607,331,000
Unamortized net deferred loan fees	(2,944,000)	(2,812,000)
Discounts to principal balance of loans owed, net of charge-offs	(37,786,000)	(39,696,000)
Total loans, net of unamortized deferred loan fees	1,532,362,000	1,564,823,000
Noncovered loans	1,492,570,000	1,522,935,000
Covered loans	39,792,000	41,888,000
Total loans, net of unamortized deferred loan fees	1,532,362,000	1,564,823,000
Allowance for loan losses	(39,867,000)	(42,648,000)	(45,452,000)	(45,914,000)
Auto Indirect [Member]
Consumer:
Total consumer loans	2,821,000	3,816,000
Other [Member]
Consumer:
Total consumer loans	27,115,000	26,713,000
Home equity lines of credit [Member]
Consumer:
Total consumer loans	333,044,000	342,025,000
Home equity loans [Member]
Consumer:
Total consumer loans	13,083,000	13,557,000
Residential [Member]
Construction:
Total construction	19,521,000	18,459,000
Commercial [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	874,289,000	878,446,000
Construction:
Total construction	11,046,000	14,595,000
Residential 1-4 family [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	135,960,000	131,684,000
Originated [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	898,171,000	896,379,000
Consumer:
Total consumer loans	343,818,000	352,761,000
Commercial	106,275,000	125,122,000
Construction:
Total construction	24,407,000	23,073,000
Total loans, net of deferred loan fees	1,372,671,000	1,397,335,000
Total principal balance of loans owed-net of charge-offs	1,375,615,000	1,400,147,000
Unamortized net deferred loan fees	(2,944,000)	(2,812,000)
Discounts to principal balance of loans owed, net of charge-offs
Total loans, net of unamortized deferred loan fees	1,372,671,000	1,397,335,000
Noncovered loans	1,372,671,000	1,397,335,000
Covered loans
Total loans, net of unamortized deferred loan fees	1,372,671,000	1,397,335,000
Allowance for loan losses	32,698,000	(35,769,000)
Originated [Member] | Auto Indirect [Member]
Consumer:
Total consumer loans	2,821,000	3,816,000
Originated [Member] | Other [Member]
Consumer:
Total consumer loans	24,826,000	24,263,000
Originated [Member] | Home equity lines of credit [Member]
Consumer:
Total consumer loans	303,638,000	311,671,000
Originated [Member] | Home equity loans [Member]
Consumer:
Total consumer loans	12,533,000	13,011,000
Originated [Member] | Residential [Member]
Construction:
Total construction	14,498,000	11,877,000
Originated [Member] | Commercial [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	772,296,000	775,124,000
Construction:
Total construction	9,909,000	11,196,000
Originated [Member] | Residential 1-4 family [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	125,875,000	121,255,000
PNCI [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	75,057,000	77,503,000
Consumer:
Total consumer loans	18,952,000	19,548,000
Commercial	779,000	869,000
Construction:
Total construction
Total loans, net of deferred loan fees	94,788,000	97,920,000
Total principal balance of loans owed-net of charge-offs	107,268,000	111,286,000
Unamortized net deferred loan fees
Discounts to principal balance of loans owed, net of charge-offs	(12,480,000)	(13,366,000)
Total loans, net of unamortized deferred loan fees	94,788,000	97,920,000
Noncovered loans	94,788,000	97,920,000
Covered loans
Total loans, net of unamortized deferred loan fees	94,788,000	97,920,000
Allowance for loan losses	2,867,000	(1,969,000)
PNCI [Member] | Auto Indirect [Member]
Consumer:
Total consumer loans
PNCI [Member] | Other [Member]
Consumer:
Total consumer loans	2,264,000	2,418,000
PNCI [Member] | Home equity lines of credit [Member]
Consumer:
Total consumer loans	16,341,000	16,788,000
PNCI [Member] | Home equity loans [Member]
Consumer:
Total consumer loans	347,000	342,000
PNCI [Member] | Residential [Member]
Construction:
Total construction
PNCI [Member] | Commercial [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	69,982,000	72,090,000
Construction:
Total construction
PNCI [Member] | Residential 1-4 family [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	5,075,000	5,413,000
PCI- Cash basis [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate		1,289,000
Consumer:
Total consumer loans	7,461,000	7,661,000
Commercial	36,000	22,000
Construction:
Total construction
Total loans, net of deferred loan fees	7,497,000	8,972,000
Total principal balance of loans owed-net of charge-offs	18,783,000	20,621,000
Unamortized net deferred loan fees
Discounts to principal balance of loans owed, net of charge-offs	(11,286,000)	(11,649,000)
Total loans, net of unamortized deferred loan fees	7,497,000	8,972,000
Noncovered loans	7,497,000	8,972,000
Covered loans
Total loans, net of unamortized deferred loan fees	7,497,000	8,972,000
Allowance for loan losses	1,039,000	(1,054,000)
PCI- Cash basis [Member] | Auto Indirect [Member]
Consumer:
Total consumer loans
PCI- Cash basis [Member] | Other [Member]
Consumer:
Total consumer loans
PCI- Cash basis [Member] | Home equity lines of credit [Member]
Consumer:
Total consumer loans	7,413,000	7,612,000
PCI- Cash basis [Member] | Home equity loans [Member]
Consumer:
Total consumer loans	48,000	49,000
PCI- Cash basis [Member] | Residential [Member]
Construction:
Total construction
PCI- Cash basis [Member] | Commercial [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate		1,289,000
Construction:
Total construction
PCI- Cash basis [Member] | Residential 1-4 family [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate
PCI- Other [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	37,021,000	34,959,000
Consumer:
Total consumer loans	5,832,000	6,141,000
Commercial	8,393,000	9,515,000
Construction:
Total construction	6,160,000	9,981,000
Total loans, net of deferred loan fees	57,406,000	60,596,000
Total principal balance of loans owed-net of charge-offs	71,426,000	75,277,000
Unamortized net deferred loan fees
Discounts to principal balance of loans owed, net of charge-offs	(14,020,000)	(14,681,000)
Total loans, net of unamortized deferred loan fees	57,406,000	60,596,000
Noncovered loans	17,614,000	18,708,000
Covered loans	39,792,000	41,888,000
Total loans, net of unamortized deferred loan fees	57,406,000	60,596,000
Allowance for loan losses	3,263,000	(3,856,000)
PCI- Other [Member] | Auto Indirect [Member]
Consumer:
Total consumer loans
PCI- Other [Member] | Other [Member]
Consumer:
Total consumer loans	25,000	32,000
PCI- Other [Member] | Home equity lines of credit [Member]
Consumer:
Total consumer loans	5,652,000	5,954,000
PCI- Other [Member] | Home equity loans [Member]
Consumer:
Total consumer loans	155,000	155,000
PCI- Other [Member] | Residential [Member]
Construction:
Total construction	5,023,000	6,582,000
PCI- Other [Member] | Commercial [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	32,011,000	29,943,000
Construction:
Total construction	1,137,000	3,399,000
PCI- Other [Member] | Residential 1-4 family [Member]
Mortgage loans on real estate:
Total mortgage loan on real estate	$ 5,010,000	$ 5,016,000