Loans Schedule of Recorded Investment in Impaired Loans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	$ 93,578		$ 93,578		$ 124,867
Recorded Investment With No Allowance	50,938		50,938		62,724
Recorded Investment With Allowance	34,120		34,120		47,848
Total Recorded Investment	85,058		85,058		110,572
Related Allowance	6,570		6,570		8,929
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	97,078	116,759	104,059	124,792
Income Recognized	270	286	825	1,413
Interest Income on Impaired Loans If Interest Had Been Accrued	1,246	1,481	3,927	4,832
Commercial real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	47,675		47,675		64,780
Recorded Investment With No Allowance	24,184		24,184		29,216
Recorded Investment With Allowance	21,603		21,603		33,937
Total Recorded Investment	45,787		45,787		63,153
Related Allowance	2,993		2,993		5,210
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	53,492	62,208	57,743	65,726
Income Recognized	211	239	668	849
Land acquisition & development construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	14,162		14,162		23,906
Recorded Investment With No Allowance	7,162		7,162		9,901
Recorded Investment With Allowance	3,366		3,366		7,226
Total Recorded Investment	10,528		10,528		17,127
Related Allowance	590		590		1,434
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	11,611	17,614	13,529	19,923
Income Recognized	11	19	33	475
Residential construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	382		382		1,816
Recorded Investment With No Allowance	238		238		1,095
Recorded Investment With Allowance	0		0		277
Total Recorded Investment	238		238		1,372
Related Allowance	0		0		26
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	304	1,513	799	1,949
Income Recognized	0	0	0	0
Commercial construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	2,736		2,736		397
Recorded Investment With No Allowance	258		258		279
Recorded Investment With Allowance	2,444		2,444		84
Total Recorded Investment	2,702		2,702		363
Related Allowance	906		906		85
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	2,709	1,174	1,520	5,161
Income Recognized	2	2	6	2
Total construction loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	17,280		17,280		26,119
Recorded Investment With No Allowance	7,658		7,658		11,275
Recorded Investment With Allowance	5,810		5,810		7,587
Total Recorded Investment	13,468		13,468		18,862
Related Allowance	1,496		1,496		1,545
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	14,624	20,301	15,848	27,033
Income Recognized	13	21	39	477
Residential real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	2,621		2,621		9,448
Recorded Investment With No Allowance	2,083		2,083		5,081
Recorded Investment With Allowance	371		371		967
Total Recorded Investment	2,454		2,454		6,048
Related Allowance	124		124		249
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	4,773	7,770	5,537	8,882
Income Recognized	1	6	4	15
Agricultural real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	8,942		8,942		8,895
Recorded Investment With No Allowance	7,074		7,074		6,429
Recorded Investment With Allowance	1,772		1,772		2,370
Total Recorded Investment	8,846		8,846		8,799
Related Allowance	192		192		335
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	9,031	9,995	10,223	7,751
Income Recognized	25	0	54	8
Total real estate loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	76,518		76,518		109,242
Recorded Investment With No Allowance	40,999		40,999		52,001
Recorded Investment With Allowance	29,556		29,556		44,861
Total Recorded Investment	70,555		70,555		96,862
Related Allowance	4,805		4,805		7,339
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	81,920	100,274	89,351	109,392
Income Recognized	250	266	765	1,349
Commercial
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	16,174		16,174		15,448
Recorded Investment With No Allowance	9,560		9,560		10,684
Recorded Investment With Allowance	4,109		4,109		2,901
Total Recorded Investment	13,669		13,669		13,585
Related Allowance	1,445		1,445		1,504
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	14,252	16,245	14,001	15,065
Income Recognized	14	16	42	52
Agricultural
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	886		886		177
Recorded Investment With No Allowance	379		379		39
Recorded Investment With Allowance	455		455		86
Total Recorded Investment	834		834		125
Related Allowance	320		320		86
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	906	240	707	335
Income Recognized	$ 6	$ 4	$ 18	$ 12