Loans Schedule of Recorded Investment in Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	$ 120,989		$ 120,989		$ 87,240
Recorded Investment With No Allowance	55,747		55,747		57,050
Recorded Investment With Allowance	36,486		36,486		21,430
Total Recorded Investment	92,233		92,233		78,480
Related Allowance	8,917		8,917		5,792
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	82,674	$ 97,078	80,836	$ 104,059
Income Recognized	305	270	860	825
Interest Income on Impaired Loans If Interest Had Been Accrued	998	1,246	2,932	3,927
Commercial real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	55,910		55,910		41,603
Recorded Investment With No Allowance	26,265		26,265		28,143
Recorded Investment With Allowance	17,131		17,131		11,246
Total Recorded Investment	43,396		43,396		39,389
Related Allowance	1,451		1,451		1,608
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	36,075	53,492	38,639	57,743
Income Recognized	226	211	587	668
Land acquisition & development construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	19,349		19,349		12,511
Recorded Investment With No Allowance	9,509		9,509		7,262
Recorded Investment With Allowance	1,212		1,212		1,615
Total Recorded Investment	10,721		10,721		8,877
Related Allowance	254		254		574
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	9,325	11,611	9,591	13,529
Income Recognized	29	11	51	33
Residential construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	1,037		1,037		459
Recorded Investment With No Allowance	329		329		272
Recorded Investment With Allowance	0		0		0
Total Recorded Investment	329		329		272
Related Allowance	0		0		0
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	330	304	300	799
Income Recognized	0	0	0	0
Commercial construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	1,290		1,290		2,729
Recorded Investment With No Allowance	369		369		253
Recorded Investment With Allowance	740		740		2,442
Total Recorded Investment	1,109		1,109		2,695
Related Allowance	740		740		904
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	2,339	2,709	1,902	1,520
Income Recognized	4	2	6	6
Total construction loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	21,676		21,676		15,699
Recorded Investment With No Allowance	10,207		10,207		7,787
Recorded Investment With Allowance	1,952		1,952		4,057
Total Recorded Investment	12,159		12,159		11,844
Related Allowance	994		994		1,478
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	11,994	14,624	11,793	15,848
Income Recognized	33	13	57	39
Residential real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	3,664		3,664		2,959
Recorded Investment With No Allowance	2,186		2,186		2,452
Recorded Investment With Allowance	645		645		341
Total Recorded Investment	2,831		2,831		2,793
Related Allowance	148		148		143
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	2,607	4,773	2,720	5,537
Income Recognized	4	1	6	4
Agricultural real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	9,043		9,043		8,844
Recorded Investment With No Allowance	6,407		6,407		6,444
Recorded Investment With Allowance	2,191		2,191		2,305
Total Recorded Investment	8,598		8,598		8,749
Related Allowance	708		708		732
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	8,578	9,031	8,661	10,223
Income Recognized	27	25	62	54
Total real estate loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	90,293		90,293		69,105
Recorded Investment With No Allowance	45,065		45,065		44,826
Recorded Investment With Allowance	21,919		21,919		17,949
Total Recorded Investment	66,984		66,984		62,775
Related Allowance	3,301		3,301		3,961
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	59,254	81,920	61,813	89,351
Income Recognized	290	250	712	765
Commercial
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	28,653		28,653		16,904
Recorded Investment With No Allowance	10,315		10,315		11,882
Recorded Investment With Allowance	13,461		13,461		2,644
Total Recorded Investment	23,776		23,776		14,526
Related Allowance	5,154		5,154		1,190
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	22,483	14,252	18,175	14,001
Income Recognized	2	14	122	42
Agricultural
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	2,043		2,043		1,231
Recorded Investment With No Allowance	367		367		342
Recorded Investment With Allowance	1,106		1,106		837
Total Recorded Investment	1,473		1,473		1,179
Related Allowance	462		462		$ 641
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	937	906	848	707
Income Recognized	$ 13	$ 6	$ 26	$ 18