Loans and Allowance for Loan Losses - Disaggregated analysis of activity in for allowances for non acquired loans - (Details 6) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for loan losses:
Charge-offs	$ (8,967)	$ (9,047)	$ (15,289)
Recoveries	3,188	3,178	4,224
Provision (benefit)	5,864	6,590	1,886
Non-acquired loans
Allowance for loan losses:
Balance at beginning of period	34,539	34,331	44,378
Charge-offs	(6,180)	(7,516)	(15,289)
Recoveries	2,801	2,574	4,224
Provision (benefit)	2,930	5,150	1,018
Balance at end of period	34,090	34,539	34,331
Loans individually evaluated for impairment	1,607	1,558	1,631
Loans collectively evaluated for impairment	32,483	32,981	32,700
Loans:
Loans individually evaluated for impairment	30,218	27,085	26,047
Loans collectively evaluated for impairment	4,190,508	3,440,741	2,839,169
Total loans	4,220,726	3,467,826	2,865,216
Non-acquired loans | Commercial non-owner occupied real estate
Loans:
Total loans	889,756	697,811
Non-acquired loans | Consumer real estate
Loans:
Total loans	1,338,239	1,070,712
Non-acquired loans | Commercial owner occupied real estate
Allowance for loan losses:
Balance at beginning of period	8,415	7,767	8,743
Charge-offs	(851)	(531)	(2,695)
Recoveries	31	95	41
Provision (benefit)	746	1,084	1,678
Balance at end of period	8,341	8,415	7,767
Loans individually evaluated for impairment	101	172	10
Loans collectively evaluated for impairment	8,240	8,243	7,757
Loans:
Loans individually evaluated for impairment	7,725	9,160	11,560
Loans collectively evaluated for impairment	1,025,673	898,753	821,953
Total loans	1,033,398	907,913	833,513
Non-acquired loans | Commercial and industrial
Allowance for loan losses:
Balance at beginning of period	3,561	3,592	4,939
Charge-offs	(357)	(1,114)	(1,329)
Recoveries	844	264	514
Provision (benefit)	(74)	819	(532)
Balance at end of period	3,974	3,561	3,592
Loans individually evaluated for impairment	279	41
Loans collectively evaluated for impairment	3,695	3,520	3,592
Loans:
Loans individually evaluated for impairment	1,487	908	405
Loans collectively evaluated for impairment	502,321	405,015	321,419
Total loans	503,808	405,923	321,824
Non-acquired loans | Other income producing property
Allowance for loan losses:
Balance at beginning of period	2,232	2,509	3,747
Charge-offs	(102)	(309)	(816)
Recoveries	85	191	224
Provision (benefit)	(252)	(159)	(646)
Balance at end of period	1,963	2,232	2,509
Loans individually evaluated for impairment	422	646	646
Loans collectively evaluated for impairment	1,541	1,586	1,863
Loans:
Loans individually evaluated for impairment	4,891	5,498	2,649
Loans collectively evaluated for impairment	170,957	145,430	140,555
Total loans	175,848	150,928	143,204
Non-acquired loans | Consumer
Allowance for loan losses:
Balance at beginning of period	1,367	937	781
Charge-offs	(3,574)	(3,501)	(2,452)
Recoveries	1,011	873	836
Provision (benefit)	2,890	3,058	1,772
Balance at end of period	1,694	1,367	937
Loans individually evaluated for impairment	3	2
Loans collectively evaluated for impairment	1,691	1,365	937
Loans:
Loans individually evaluated for impairment	102	60
Loans collectively evaluated for impairment	233,002	189,257	136,410
Total loans	233,104	189,317	136,410
Non-acquired loans | Other Loans
Allowance for loan losses:
Balance at beginning of period	449	209	217
Provision (benefit)	(156)	240	(8)
Balance at end of period	293	449	209
Loans individually evaluated for impairment	12
Loans collectively evaluated for impairment	281	449	209
Loans:
Loans individually evaluated for impairment	423
Loans collectively evaluated for impairment	46,150	45,222	33,834
Total loans	46,573	45,222	33,834
Non-acquired loans | Construction and land development | Commercial non-owner occupied real estate
Allowance for loan losses:
Balance at beginning of period	5,666	6,789	10,836
Charge-offs	(219)	(237)	(4,656)
Recoveries	376	421	1,395
Provision (benefit)	(1,707)	(1,307)	(786)
Balance at end of period	4,116	5,666	6,789
Loans individually evaluated for impairment	615	475	704
Loans collectively evaluated for impairment	3,501	5,191	6,085
Loans:
Loans individually evaluated for impairment	6,280	4,852	5,739
Loans collectively evaluated for impairment	395,699	359,369	294,212
Total loans	401,979	364,221	299,951
Non-acquired loans | Other commercial non-owner occupied real estate | Commercial non-owner occupied real estate
Allowance for loan losses:
Balance at beginning of period	3,154	3,677	4,921
Charge-offs	(156)	(442)	(660)
Recoveries	67	390	353
Provision (benefit)	503	(471)	(937)
Balance at end of period	3,568	3,154	3,677
Loans individually evaluated for impairment	34	77
Loans collectively evaluated for impairment	3,534	3,077	3,677
Loans:
Loans individually evaluated for impairment	1,452	3,610	2,681
Loans collectively evaluated for impairment	486,325	329,980	288,490
Total loans	487,777	333,590	291,171
Non-acquired loans | Consumer owner occupied | Consumer real estate
Allowance for loan losses:
Balance at beginning of period	6,866	6,069	6,568
Charge-offs	(374)	(382)	(1,462)
Recoveries	143	271	633
Provision (benefit)	577	908	330
Balance at end of period	7,212	6,866	6,069
Loans individually evaluated for impairment	138	144	271
Loans collectively evaluated for impairment	7,074	6,722	5,798
Loans:
Loans individually evaluated for impairment	7,549	2,966	3,013
Loans collectively evaluated for impairment	1,011,435	783,812	545,157
Total loans	1,018,984	786,778	548,170
Non-acquired loans | Home equity loans | Consumer real estate
Allowance for loan losses:
Balance at beginning of period	2,829	2,782	3,626
Charge-offs	(547)	(1,000)	(1,219)
Recoveries	244	69	228
Provision (benefit)	403	978	147
Balance at end of period	2,929	2,829	2,782
Loans individually evaluated for impairment	3	1
Loans collectively evaluated for impairment	2,926	2,828	2,782
Loans:
Loans individually evaluated for impairment	309	31
Loans collectively evaluated for impairment	318,946	283,903	257,139
Total loans	319,255	283,934	257,139
Acquired non-credit impaired loans
Allowance for loan losses:
Charge-offs	(2,787)	(1,531)
Recoveries	387	604
Provision (benefit)	2,400	927
Loans:
Loans collectively evaluated for impairment	1,049,538	1,327,999
Total loans	1,049,538	1,327,999
Acquired non-credit impaired loans | Commercial owner occupied real estate
Loans:
Loans collectively evaluated for impairment	39,220	62,065
Total loans	39,220	62,065
Acquired non-credit impaired loans | Commercial and industrial
Allowance for loan losses:
Charge-offs	(118)	(456)
Recoveries	19	312
Provision (benefit)	99	144
Loans:
Loans collectively evaluated for impairment	25,475	41,130
Total loans	25,475	41,130
Acquired non-credit impaired loans | Other income producing property
Allowance for loan losses:
Charge-offs	(4)	(14)
Recoveries	4
Provision (benefit)		14
Loans:
Loans collectively evaluated for impairment	51,169	65,139
Total loans	51,169	65,139
Acquired non-credit impaired loans | Consumer
Allowance for loan losses:
Charge-offs	(643)	(231)
Recoveries	21	9
Provision (benefit)	622	222
Loans:
Loans collectively evaluated for impairment	170,647	204,766
Total loans	170,647	204,766
Acquired non-credit impaired loans | Construction and land development | Commercial non-owner occupied real estate
Allowance for loan losses:
Charge-offs		(78)
Recoveries	4	1
Provision (benefit)	(4)	77
Loans:
Loans collectively evaluated for impairment	13,849	24,099
Total loans	13,849	24,099
Acquired non-credit impaired loans | Other commercial non-owner occupied real estate | Commercial non-owner occupied real estate
Allowance for loan losses:
Charge-offs		(72)
Provision (benefit)		72
Loans:
Loans collectively evaluated for impairment	40,103	49,476
Total loans	40,103	49,476
Acquired non-credit impaired loans | Consumer owner occupied | Consumer real estate
Allowance for loan losses:
Charge-offs	(360)	(150)
Recoveries	102	20
Provision (benefit)	258	130
Loans:
Loans collectively evaluated for impairment	518,107	646,375
Total loans	518,107	646,375
Acquired non-credit impaired loans | Home equity loans | Consumer real estate
Allowance for loan losses:
Charge-offs	(1,662)	(530)
Recoveries	237	262
Provision (benefit)	1,425	268
Loans:
Loans collectively evaluated for impairment	190,968	234,949
Total loans	190,968	234,949
Acquired credit impaired loans
Allowance for loan losses:
Provision (benefit)	534	513	868
Loans collectively evaluated for impairment	3,706	7,365	11,618
Loans:
Loans collectively evaluated for impairment	737,576	926,767	1,232,256
Acquired credit impaired loans | Commercial Loans Greater Than or Equal to $1 Million-CBT
Allowance for loan losses:
Provision (benefit)	(43)	54	(175)
Loans collectively evaluated for impairment		135	303
Loans:
Loans collectively evaluated for impairment	12,628	15,813	24,109
Acquired credit impaired loans | Residential real estate
Allowance for loan losses:
Provision (benefit)	327	165	537
Loans collectively evaluated for impairment	2,986	4,387	5,132
Loans:
Loans collectively evaluated for impairment	313,319	390,244	481,247
Acquired credit impaired loans | Consumer real estate
Allowance for loan losses:
Provision (benefit)	229	30	30
Loans collectively evaluated for impairment	313	275	538
Loans:
Loans collectively evaluated for impairment	70,734	85,449	103,998
Acquired credit impaired loans | Commercial and industrial
Allowance for loan losses:
Provision (benefit)	13	57	(67)
Loans collectively evaluated for impairment	174	718	1,481
Loans:
Loans collectively evaluated for impairment	31,193	44,804	68,862
Acquired credit impaired loans | Single pay
Allowance for loan losses:
Provision (benefit)	(1)		(2)
Loans collectively evaluated for impairment		70	104
Loans:
Loans collectively evaluated for impairment		86	129
Acquired credit impaired loans | Construction and land development | Commercial non-owner occupied real estate
Allowance for loan losses:
Provision (benefit)	6	171	702
Loans collectively evaluated for impairment	177	336	2,244
Loans:
Loans collectively evaluated for impairment	54,272	65,262	114,126
Acquired credit impaired loans | Other commercial non-owner occupied real estate | Commercial non-owner occupied real estate
Allowance for loan losses:
Provision (benefit)	3	36	(157)
Loans collectively evaluated for impairment	56	1,444	1,816
Loans:
Loans collectively evaluated for impairment	$ 255,430	$ 325,109	$ 439,785