Loans and Allowance for Loan Losses - Disaggregated analysis of activity in for allowances for non acquired loans - (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Allowance for loan losses:
Charge-offs	$ (1,388)	$ (1,671)	$ (5,194)	$ (6,716)
Recoveries	833	928	2,620	2,576
Provision (benefit)	912	1,075	6,198	5,038
Non-acquired loans
Allowance for loan losses:
Balance at beginning of period	36,939	34,782	34,090	34,539
Charge-offs	(1,108)	(1,530)	(4,384)	(4,206)
Recoveries	713	655	2,358	2,253
Provision (benefit)	775	1,209	5,255	2,530
Balance at end of period	37,319	35,116	37,319	35,116
Loans individually evaluated for impairment	1,379	1,456	1,379	1,456
Loans collectively evaluated for impairment	35,940	33,660	35,940	33,660
Loans:
Loans individually evaluated for impairment	21,187	34,479	21,187	34,479
Loans collectively evaluated for impairment	4,986,926	3,960,237	4,986,926	3,960,237
Total loans	5,008,113	3,994,716	5,008,113	3,994,716	$ 4,220,726
Acquired credit impaired loans
Allowance for loan losses:
Balance at beginning of period			3,706	7,365
Provision (benefit)	(23)	(2)	395	321
Loans collectively evaluated for impairment	3,403	4,474	3,403	4,474
Loans:
Loans collectively evaluated for impairment	636,020	773,080	636,020	773,080
Total loans	636,020	773,080	636,020	773,080
Acquired non-credit impaired loans
Allowance for loan losses:
Charge-offs	(280)	(141)	(810)	(2,510)
Recoveries	120	273	262	323
Provision (benefit)	160	(132)	548	2,187
Loans:
Loans collectively evaluated for impairment	885,657	1,107,440	885,657	1,107,440
Total loans	885,657	1,107,440	885,657	1,107,440
Residential real estate | Acquired credit impaired loans
Allowance for loan losses:
Balance at beginning of period			2,986	4,387
Provision (benefit)	2	(160)	(155)	(138)
Loans collectively evaluated for impairment	2,492	2,863	2,492	2,863
Loans:
Loans collectively evaluated for impairment	268,968	330,754	268,968	330,754
Total loans	268,968	330,754	268,968	330,754
Commercial non-owner occupied real estate | Non-acquired loans
Loans:
Total loans	1,192,773	778,566	1,192,773	778,566	889,756
Commercial non-owner occupied real estate | Non-acquired loans | Construction and land development
Allowance for loan losses:
Balance at beginning of period	4,665	4,998	4,116	5,666
Charge-offs		(85)	(159)	(185)
Recoveries	241	122	848	256
Provision (benefit)	(795)	(826)	(694)	(1,528)
Balance at end of period	4,111	4,209	4,111	4,209
Loans individually evaluated for impairment	359	585	359	585
Loans collectively evaluated for impairment	3,752	3,624	3,752	3,624
Loans:
Loans individually evaluated for impairment	3,431	5,727	3,431	5,727
Loans collectively evaluated for impairment	558,905	366,350	558,905	366,350
Total loans	562,336	372,077	562,336	372,077	401,979
Commercial non-owner occupied real estate | Non-acquired loans | Other commercial non-owner occupied real estate
Allowance for loan losses:
Balance at beginning of period	4,656	3,038	3,568	3,154
Charge-offs		(5)		(88)
Recoveries	28	23	59	52
Provision (benefit)	(93)	268	964	206
Balance at end of period	4,591	3,324	4,591	3,324
Loans individually evaluated for impairment	181	26	181	26
Loans collectively evaluated for impairment	4,410	3,298	4,410	3,298
Loans:
Loans individually evaluated for impairment	764	2,569	764	2,569
Loans collectively evaluated for impairment	629,673	403,920	629,673	403,920
Total loans	630,437	406,489	630,437	406,489	487,777
Commercial non-owner occupied real estate | Acquired credit impaired loans | Construction and land development
Allowance for loan losses:
Balance at beginning of period			177	336
Provision (benefit)		433		443
Loans collectively evaluated for impairment	145	728	145	728
Loans:
Loans collectively evaluated for impairment	47,081	55,168	47,081	55,168
Total loans	47,081	55,168	47,081	55,168
Commercial non-owner occupied real estate | Acquired credit impaired loans | Other commercial non-owner occupied real estate
Allowance for loan losses:
Balance at beginning of period			56	1,444
Provision (benefit)			1	3
Loans collectively evaluated for impairment	40	525	40	525
Loans:
Loans collectively evaluated for impairment	220,489	266,465	220,489	266,465
Total loans	220,489	266,465	220,489	266,465
Commercial non-owner occupied real estate | Acquired non-credit impaired loans | Construction and land development
Allowance for loan losses:
Recoveries	1	1	3	3
Provision (benefit)	(1)	(1)	(3)	(3)
Loans:
Loans collectively evaluated for impairment	10,683	16,482	10,683	16,482
Total loans	10,683	16,482	10,683	16,482
Commercial non-owner occupied real estate | Acquired non-credit impaired loans | Other commercial non-owner occupied real estate
Loans:
Loans collectively evaluated for impairment	35,775	42,172	35,775	42,172
Total loans	35,775	42,172	35,775	42,172
Commercial owner occupied real estate loan | Non-acquired loans
Allowance for loan losses:
Balance at beginning of period	8,003	8,684	8,341	8,415
Charge-offs	(16)	(23)	(117)	(575)
Recoveries	25	7	46	23
Provision (benefit)	516	376	258	1,181
Balance at end of period	8,528	9,044	8,528	9,044
Loans individually evaluated for impairment	65	248	65	248
Loans collectively evaluated for impairment	8,463	8,796	8,463	8,796
Loans:
Loans individually evaluated for impairment	6,352	11,445	6,352	11,445
Loans collectively evaluated for impairment	1,147,128	1,000,983	1,147,128	1,000,983
Total loans	1,153,480	1,012,428	1,153,480	1,012,428	1,033,398
Commercial owner occupied real estate loan | Acquired non-credit impaired loans
Allowance for loan losses:
Charge-offs	(3)		(3)
Provision (benefit)	3		3
Loans:
Loans collectively evaluated for impairment	29,444	42,524	29,444	42,524
Total loans	29,444	42,524	29,444	42,524
Consumer real estate | Non-acquired loans
Loans:
Total loans	1,547,266	1,296,426	1,547,266	1,296,426	1,338,239
Consumer real estate | Non-acquired loans | Home equity loans
Allowance for loan losses:
Balance at beginning of period	3,148	2,868	2,929	2,829
Charge-offs		(74)	(767)	(282)
Recoveries	64	91	239	201
Provision (benefit)	69	26	880	163
Balance at end of period	3,281	2,911	3,281	2,911
Loans individually evaluated for impairment	38	3	38	3
Loans collectively evaluated for impairment	3,243	2,908	3,243	2,908
Loans:
Loans individually evaluated for impairment	1,599	293	1,599	293
Loans collectively evaluated for impairment	362,226	308,270	362,226	308,270
Total loans	363,825	308,563	363,825	308,563	319,255
Consumer real estate | Non-acquired loans | Consumer
Loans:
Total loans	1,864,740	1,571,137	1,864,740	1,571,137	1,617,916
Consumer real estate | Non-acquired loans | Consumer Owner Occupied Loans
Allowance for loan losses:
Balance at beginning of period	7,530	7,125	7,212	6,866
Charge-offs	(45)	(230)	(174)	(274)
Recoveries	27	89	125	134
Provision (benefit)	338	471	687	729
Balance at end of period	7,850	7,455	7,850	7,455
Loans individually evaluated for impairment	58	121	58	121
Loans collectively evaluated for impairment	7,792	7,334	7,792	7,334
Loans:
Loans individually evaluated for impairment	3,127	7,818	3,127	7,818
Loans collectively evaluated for impairment	1,180,314	980,045	1,180,314	980,045
Total loans	1,183,441	987,863	1,183,441	987,863	1,018,984
Consumer real estate | Acquired credit impaired loans
Allowance for loan losses:
Balance at beginning of period			313	275
Provision (benefit)	(23)	(249)	511	34
Loans collectively evaluated for impairment	544	156	544	156
Loans:
Loans collectively evaluated for impairment	61,866	73,632	61,866	73,632
Total loans	61,866	73,632	61,866	73,632
Consumer real estate | Acquired non-credit impaired loans | Home equity loans
Allowance for loan losses:
Charge-offs	(105)	(79)	(292)	(1,459)
Recoveries	89	161	197	178
Provision (benefit)	16	(82)	95	1,281
Loans:
Loans collectively evaluated for impairment	168,758	203,025	168,758	203,025
Total loans	168,758	203,025	168,758	203,025
Consumer real estate | Acquired non-credit impaired loans | Consumer Owner Occupied Loans
Allowance for loan losses:
Charge-offs				(360)
Charge-offs (added back)		8
Recoveries	3	95	9	100
Provision (benefit)	(3)	(103)	(9)	260
Loans:
Loans collectively evaluated for impairment	435,132	542,278	435,132	542,278
Total loans	435,132	542,278	435,132	542,278
Commercial and industrial | Non-acquired loans
Allowance for loan losses:
Balance at beginning of period	4,269	3,983	3,974	3,561
Charge-offs	(31)	(102)	(358)	(357)
Recoveries	104	79	207	745
Provision (benefit)	368	16	887	27
Balance at end of period	4,710	3,976	4,710	3,976
Loans individually evaluated for impairment	385	21	385	21
Loans collectively evaluated for impairment	4,325	3,955	4,325	3,955
Loans:
Loans individually evaluated for impairment	1,453	1,045	1,453	1,045
Loans collectively evaluated for impairment	616,072	461,543	616,072	461,543
Total loans	617,525	462,588	617,525	462,588	503,808
Commercial and industrial | Acquired credit impaired loans
Allowance for loan losses:
Balance at beginning of period			174	718
Provision (benefit)	(2)	15	38	20
Loans collectively evaluated for impairment	182	200	182	200
Loans:
Loans collectively evaluated for impairment	26,658	34,074	26,658	34,074
Total loans	26,658	34,074	26,658	34,074
Commercial and industrial | Acquired non-credit impaired loans
Allowance for loan losses:
Charge-offs	(23)	(7)	(30)	(120)
Recoveries	1	2	3	17
Provision (benefit)	22	5	27	103
Loans:
Loans collectively evaluated for impairment	14,201	27,459	14,201	27,459
Total loans	14,201	27,459	14,201	27,459
Other income producing property | Non-acquired loans
Allowance for loan losses:
Balance at beginning of period	1,812	2,019	1,963	2,232
Charge-offs			(7)	(13)
Recoveries	8	11	47	77
Provision (benefit)	(201)	(3)	(384)	(269)
Balance at end of period	1,619	2,027	1,619	2,027
Loans individually evaluated for impairment	289	430	289	430
Loans collectively evaluated for impairment	1,330	1,597	1,330	1,597
Loans:
Loans individually evaluated for impairment	4,319	4,788	4,319	4,788
Loans collectively evaluated for impairment	175,276	165,209	175,276	165,209
Total loans	179,595	169,997	179,595	169,997	175,848
Other income producing property | Acquired non-credit impaired loans
Allowance for loan losses:
Charge-offs				(3)
Recoveries		3	1	4
Provision (benefit)		(3)	(1)	(1)
Loans:
Loans collectively evaluated for impairment	43,152	56,092	43,152	56,092
Total loans	43,152	56,092	43,152	56,092
Consumer | Non-acquired loans
Allowance for loan losses:
Balance at beginning of period	2,014	1,608	1,694	1,367
Charge-offs	(1,016)	(1,011)	(2,802)	(2,432)
Recoveries	216	233	787	765
Provision (benefit)	1,094	886	2,629	2,016
Balance at end of period	2,308	1,716	2,308	1,716
Loans individually evaluated for impairment	4	3	4	3
Loans collectively evaluated for impairment	2,304	1,713	2,304	1,713
Loans:
Loans individually evaluated for impairment	142	101	142	101
Loans collectively evaluated for impairment	305,545	223,109	305,545	223,109
Total loans	305,687	223,210	305,687	223,210	233,104
Consumer | Acquired non-credit impaired loans
Allowance for loan losses:
Charge-offs	(149)	(63)	(485)	(568)
Recoveries	26	11	49	21
Provision (benefit)	123	52	436	547
Loans:
Loans collectively evaluated for impairment	148,512	177,408	148,512	177,408
Total loans	148,512	177,408	148,512	177,408
Commercial | Non-acquired loans
Loans:
Total loans	3,143,373	2,423,579	3,143,373	2,423,579	2,602,810
Single pay loans | Acquired credit impaired loans
Allowance for loan losses:
Balance at beginning of period				70
Provision (benefit)		(48)		(48)
Loans collectively evaluated for impairment		2		2
Loans:
Loans collectively evaluated for impairment		24		24
Total loans		24		24
Other loans | Non-acquired loans
Allowance for loan losses:
Balance at beginning of period	842	459	293	449
Provision (benefit)	(521)	(5)	28	5
Balance at end of period	321	454	321	454
Loans individually evaluated for impairment		19		19
Loans collectively evaluated for impairment	321	435	321	435
Loans:
Loans individually evaluated for impairment		693		693
Loans collectively evaluated for impairment	11,787	50,808	11,787	50,808
Total loans	11,787	51,501	11,787	51,501	$ 46,573
Commercial loans 1000000 or more | Acquired credit impaired loans
Allowance for loan losses:
Balance at beginning of period				135
Provision (benefit)		7		7
Loans:
Loans collectively evaluated for impairment	10,958	12,963	10,958	12,963
Total loans	$ 10,958	$ 12,963	$ 10,958	$ 12,963