Loans and Allowances for Credit Losses Part 4 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	$ 335,306		$ 341,939		$ 319,534
Impaired loans, recorded investment, total	287,955		294,838		281,970
Impaired loans, recorded investment with no related allowance	282,448		291,772		279,827
Impaired loans, recorded investment with related allowance	5,507		3,066		2,143
Impaired loans, related allowance	4,159		1,027		954
Impaired loans, average recorded investment	288,738		294,606
Impaired loans, interest income recognized	2,481		1,594
Commercial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	35,809		31,764		30,826
Impaired loans, recorded investment, total	19,046		19,861		16,760
Impaired loans, recorded investment with no related allowance	14,977		18,794		15,549
Impaired loans, recorded investment with related allowance	4,069		1,067		1,211
Impaired loans, related allowance	3,433		348		573
Impaired loans, average recorded investment	17,902		22,165
Impaired loans, interest income recognized	0		0
Energy [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	1,787		2,377		1,860
Impaired loans, recorded investment, total	1,759		2,377		1,860
Impaired loans, recorded investment with no related allowance	1,759		2,377		1,860
Impaired loans, recorded investment with related allowance	0		0		0
Impaired loans, related allowance	0		0		0
Impaired loans, average recorded investment	1,809		2,419
Impaired loans, interest income recognized	0		0
Services [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	7,475		12,592		6,486
Impaired loans, recorded investment, total	4,581		9,474		4,922
Impaired loans, recorded investment with no related allowance	3,544		8,502		3,791
Impaired loans, recorded investment with related allowance	1,037		972		1,131
Impaired loans, related allowance	424		292		516
Impaired loans, average recorded investment	4,752		10,782
Impaired loans, interest income recognized	0		0
Wholesale/retail [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	11,765		2,545		11,009
Impaired loans, recorded investment, total	6,853		2,239		6,969
Impaired loans, recorded investment with no related allowance	6,821		2,187		6,937
Impaired loans, recorded investment with related allowance	32		52		32
Impaired loans, related allowance	9		13		9
Impaired loans, average recorded investment	6,911		2,658
Impaired loans, interest income recognized	0		0
Healthcare [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	2,466		3,649		2,193
Impaired loans, recorded investment, total	1,443		2,962		1,586
Impaired loans, recorded investment with no related allowance	1,443		2,919		1,538
Impaired loans, recorded investment with related allowance	0		43		48
Impaired loans, related allowance	0		43		48
Impaired loans, average recorded investment	1,514		3,064
Impaired loans, interest income recognized	0		0
Manufacturing [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	3,806		2,140		746
Impaired loans, recorded investment, total	3,565		1,848		592
Impaired loans, recorded investment with no related allowance	565		1,848		592
Impaired loans, recorded investment with related allowance	3,000		0		0
Impaired loans, related allowance	3,000		0		0
Impaired loans, average recorded investment	2,078		1,928
Impaired loans, interest income recognized	0		0
Integrated food services [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	0		0		0
Impaired loans, recorded investment, total	0		0		0
Impaired loans, recorded investment with no related allowance	0		0		0
Impaired loans, recorded investment with related allowance	0		0		0
Impaired loans, related allowance	0		0		0
Impaired loans, average recorded investment	0		342
Impaired loans, interest income recognized	0		0
Other commercial and industrial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	8,510		8,461		8,532
Impaired loans, recorded investment, total	845		961		831
Impaired loans, recorded investment with no related allowance	845		961		831
Impaired loans, recorded investment with related allowance	0		0		0
Impaired loans, related allowance	0		0		0
Impaired loans, average recorded investment	838		972
Impaired loans, interest income recognized	0		0
Commercial Real Estate [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	54,751		80,379		49,637
Impaired loans, recorded investment, total	39,305		65,175		40,850
Impaired loans, recorded investment with no related allowance	38,462		63,846		40,328
Impaired loans, recorded investment with related allowance	843		1,329		522
Impaired loans, related allowance	185		258		133
Impaired loans, average recorded investment	40,077		62,902
Impaired loans, interest income recognized	0		0
Residential construction and land development [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	20,866		28,913		20,804
Impaired loans, recorded investment, total	16,547		23,462		17,377
Impaired loans, recorded investment with no related allowance	15,893		22,967		17,050
Impaired loans, recorded investment with related allowance	654		495		327
Impaired loans, related allowance	162		155		107
Impaired loans, average recorded investment	16,962		24,797
Impaired loans, interest income recognized	0		0
Retail [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	6,462		11,375		6,133
Impaired loans, recorded investment, total	4,626		8,921		4,857
Impaired loans, recorded investment with no related allowance	4,626		8,921		4,857
Impaired loans, recorded investment with related allowance	0		0		0
Impaired loans, related allowance	0		0		0
Impaired loans, average recorded investment	4,742		8,519
Impaired loans, interest income recognized	0		0
Office [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	8,688		16,169		7,848
Impaired loans, recorded investment, total	6,301		12,851		6,391
Impaired loans, recorded investment with no related allowance	6,296		12,617		6,383
Impaired loans, recorded investment with related allowance	5		234		8
Impaired loans, related allowance	5		30		8
Impaired loans, average recorded investment	6,346		9,840
Impaired loans, interest income recognized	0		0
Multifamily [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	0		4,501		7
Impaired loans, recorded investment, total	0		4,501		7
Impaired loans, recorded investment with no related allowance	0		4,501		7
Impaired loans, recorded investment with related allowance	0		0		0
Impaired loans, related allowance	0		0		0
Impaired loans, average recorded investment	3		3,604
Impaired loans, interest income recognized	0		0
Industrial [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	1,043		3,875		252
Impaired loans, recorded investment, total	886		2,198		252
Impaired loans, recorded investment with no related allowance	886		2,198		252
Impaired loans, recorded investment with related allowance	0		0		0
Impaired loans, related allowance	0		0		0
Impaired loans, average recorded investment	569		3,083
Impaired loans, interest income recognized	0		0
Other commercial real estate [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	17,692		15,546		14,593
Impaired loans, recorded investment, total	10,945		13,242		11,966
Impaired loans, recorded investment with no related allowance	10,761		12,642		11,779
Impaired loans, recorded investment with related allowance	184		600		187
Impaired loans, related allowance	18		73		18
Impaired loans, average recorded investment	11,455		13,059
Impaired loans, interest income recognized	0		0
Residential Mortgage [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	243,757		227,559		237,843
Impaired loans, recorded investment, total	228,630		207,631		223,141
Impaired loans, recorded investment with no related allowance	228,035		207,083		222,731
Impaired loans, recorded investment with related allowance	595		548		410
Impaired loans, related allowance	541		299		248
Impaired loans, average recorded investment	229,662		207,098
Impaired loans, interest income recognized	2,481		1,594
Permanent mortage [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	45,215		48,613		41,870
Impaired loans, recorded investment, total	36,342		38,153		34,279
Impaired loans, recorded investment with no related allowance	35,747		37,605		33,869
Impaired loans, recorded investment with related allowance	595		548		410
Impaired loans, related allowance	541		299		248
Impaired loans, average recorded investment	35,310		39,008
Impaired loans, interest income recognized	345		318
Permanent mortgages guaranteed by US govenment agencies [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	191,067	[1]	171,887	[2]	188,436	[3]
Impaired loans, recorded investment, total	184,822	[1]	162,419	[2]	181,598	[3]
Impaired loans, recorded investment with no related allowance	184,822	[1]	162,419	[2]	181,598	[3]
Impaired loans, recorded investment with related allowance	0	[1]	0	[2]	0	[3]
Impaired loans, related allowance	0	[1]	0	[2]	0	[3]
Impaired loans, average recorded investment	186,987	[1]	161,432	[2]
Impaired loans, interest income recognized	2,136	[1]	1,276	[2]
Home equity {Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	7,475		7,059		7,537
Impaired loans, recorded investment, total	7,466		7,059		7,264
Impaired loans, recorded investment with no related allowance	7,466		7,059		7,264
Impaired loans, recorded investment with related allowance	0		0		0
Impaired loans, related allowance	0		0		0
Impaired loans, average recorded investment	7,365		6,658
Impaired loans, interest income recognized	0		0
Consumer [Member]
Impaired loans [Abstract]
Impaired loans, unpaid principal balance	989		2,237		1,228
Impaired loans, recorded investment, total	974		2,171		1,219
Impaired loans, recorded investment with no related allowance	974		2,049		1,219
Impaired loans, recorded investment with related allowance	0		122		0
Impaired loans, related allowance	0		122		0
Impaired loans, average recorded investment	1,097		2,441
Impaired loans, interest income recognized	$ 0		$ 0

[1] All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At March 31, 2014, $1.6 million of these loans were nonaccruing and $183 million were accruing based on the guarantee by U.S. government agencies.

[2] All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At March 31, 2013, $214 thousand of these loans were nonaccruing and $162 million were accruing based on the guarantee by U.S. government agencies.

[3] All permanent mortgage loans guaranteed by U.S. government agencies are considered impaired as we do not expect full collection of contractual principal and interest. At December 31, 2013, $777 thousand of these loans were nonaccruing and $181 million were accruing based on the guarantee by U.S. government agencies.