Loans Schedule of Recorded Investment in Impaired Loans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	$ 113,960		$ 124,867
Recorded Investment With No Allowance	64,317		62,724
Recorded Investment With Allowance	37,612		47,848
Total Recorded Investment	101,929		110,572
Related Allowance	7,494		8,929
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	109,462	135,579
Income Recognized	255	809
Interest Income on Impaired Loans If Interest Had Been Accrued	1,111	1,335
Commercial real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	58,383		64,780
Recorded Investment With No Allowance	29,901		29,216
Recorded Investment With Allowance	26,701		33,937
Total Recorded Investment	56,602		63,153
Related Allowance	4,617		5,210
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	62,312	73,936
Income Recognized	216	338
Land acquisition & development construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	17,776		23,906
Recorded Investment With No Allowance	8,679		9,901
Recorded Investment With Allowance	4,642		7,226
Total Recorded Investment	13,321		17,127
Related Allowance	597		1,434
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	15,553	22,641
Income Recognized	11	441
Residential construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	1,519		1,816
Recorded Investment With No Allowance	1,076		1,095
Recorded Investment With Allowance	0		277
Total Recorded Investment	1,076		1,372
Related Allowance	0		26
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	1,320	2,259
Income Recognized	0	0
Commercial construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	390		397
Recorded Investment With No Allowance	274		279
Recorded Investment With Allowance	83		84
Total Recorded Investment	357		363
Related Allowance	83		85
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	360	7,898
Income Recognized	2	0
Total construction loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	19,685		26,119
Recorded Investment With No Allowance	10,029		11,275
Recorded Investment With Allowance	4,725		7,587
Total Recorded Investment	14,754		18,862
Related Allowance	680		1,545
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	17,233	32,798
Income Recognized	13	441
Residential real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	9,894		9,448
Recorded Investment With No Allowance	5,536		5,081
Recorded Investment With Allowance	901		967
Total Recorded Investment	6,437		6,048
Related Allowance	380		249
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	6,128	10,519
Income Recognized	2	4
Agricultural real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	9,075		8,895
Recorded Investment With No Allowance	6,663		6,429
Recorded Investment With Allowance	2,316		2,370
Total Recorded Investment	8,979		8,799
Related Allowance	275		335
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	9,233	4,948
Income Recognized	4	4
Total real estate loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	97,037		109,242
Recorded Investment With No Allowance	52,129		52,001
Recorded Investment With Allowance	34,643		44,861
Total Recorded Investment	86,772		96,862
Related Allowance	5,952		7,339
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	94,906	122,201
Income Recognized	235	787
Commercial
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	16,178		15,448
Recorded Investment With No Allowance	11,579		10,684
Recorded Investment With Allowance	2,885		2,901
Total Recorded Investment	14,464		13,585
Related Allowance	1,458		1,504
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	14,268	12,746
Income Recognized	14	18
Agricultural
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	745		177
Recorded Investment With No Allowance	609		39
Recorded Investment With Allowance	84		86
Total Recorded Investment	693		125
Related Allowance	84		86
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	288	632
Income Recognized	$ 6	$ 4