Loans Schedule of Recorded Investment in Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	$ 133,299		$ 133,299		$ 87,240
Recorded Investment With No Allowance	58,800		58,800		57,050
Recorded Investment With Allowance	41,693		41,693		21,430
Total Recorded Investment	100,493		100,493		78,480
Related Allowance	8,721		8,721		5,792
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	86,438	$ 103,910	82,923	$ 107,961
Income Recognized	357	300	555	555
Interest Income on Impaired Loans If Interest Had Been Accrued	1,045	1,301	2,011	2,412
Commercial real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	60,786		60,786		41,603
Recorded Investment With No Allowance	31,201		31,201		28,143
Recorded Investment With Allowance	17,201		17,201		11,246
Total Recorded Investment	48,402		48,402		39,389
Related Allowance	1,810		1,810		1,608
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	39,513	57,588	40,652	60,870
Income Recognized	211	241	361	457
Land acquisition & development construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	22,630		22,630		12,511
Recorded Investment With No Allowance	6,452		6,452		7,262
Recorded Investment With Allowance	5,915		5,915		1,615
Total Recorded Investment	12,367		12,367		8,877
Related Allowance	569		569		574
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	8,664	13,563	8,720	14,554
Income Recognized	12	11	22	22
Residential construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	969		969		459
Recorded Investment With No Allowance	332		332		272
Recorded Investment With Allowance	0		0		0
Total Recorded Investment	332		332		272
Related Allowance	0		0		0
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	338	785	302	1,051
Income Recognized	0	0	0	0
Commercial construction real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	3,796		3,796		2,729
Recorded Investment With No Allowance	426		426		253
Recorded Investment With Allowance	1,590		1,590		2,442
Total Recorded Investment	2,016		2,016		2,695
Related Allowance	1,606		1,606		904
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	3,492	1,471	3,133	918
Income Recognized	0	2	2	4
Total construction loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	27,395		27,395		15,699
Recorded Investment With No Allowance	7,210		7,210		7,787
Recorded Investment With Allowance	7,505		7,505		4,057
Total Recorded Investment	14,715		14,715		11,844
Related Allowance	2,175		2,175		1,478
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	12,494	15,819	12,155	16,523
Income Recognized	12	13	24	26
Residential real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	5,442		5,442		2,959
Recorded Investment With No Allowance	2,291		2,291		2,452
Recorded Investment With Allowance	1,429		1,429		341
Total Recorded Investment	3,720		3,720		2,793
Related Allowance	127		127		143
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	3,014	5,852	2,719	5,969
Income Recognized	1	1	2	3
Agricultural real estate
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	9,094		9,094		8,844
Recorded Investment With No Allowance	6,396		6,396		6,444
Recorded Investment With Allowance	2,202		2,202		2,305
Total Recorded Investment	8,598		8,598		8,749
Related Allowance	712		712		732
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	8,572	9,747	8,666	9,830
Income Recognized	13	25	35	29
Total real estate loans
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	102,717		102,717		69,105
Recorded Investment With No Allowance	47,098		47,098		44,826
Recorded Investment With Allowance	28,337		28,337		17,949
Total Recorded Investment	75,435		75,435		62,775
Related Allowance	4,824		4,824		3,961
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	63,593	89,006	64,192	93,192
Income Recognized	237	280	422	515
Commercial
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	28,472		28,472		16,904
Recorded Investment With No Allowance	11,275		11,275		11,882
Recorded Investment With Allowance	12,298		12,298		2,644
Total Recorded Investment	23,573		23,573		14,526
Related Allowance	3,279		3,279		1,190
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	21,841	14,162	17,874	14,231
Income Recognized	112	14	120	28
Agricultural
Impaired Financing Receivable, Unpaid Principal Balance
Unpaid Total Principal Balance	2,110		2,110		1,231
Recorded Investment With No Allowance	427		427		342
Recorded Investment With Allowance	1,058		1,058		837
Total Recorded Investment	1,485		1,485		1,179
Related Allowance	618		618		$ 641
Impaired Financing Receivable, Average Recorded Investment and Cash Basis Method Interest Income
Average Recorded Investment	1,004	742	857	538
Income Recognized	$ 8	$ 6	$ 13	$ 12