Loans and Allowance for Loan Losses - Credit risk profile by risk grade of non acquired loans - (Details 8) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Loans and Allowance for Loan Losses
Other Real Estate, Non Covered	$ 24,803	$ 26,499	$ 37,398	$ 32,248
Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	4,220,726	3,467,826	2,865,216
Classified Assets	56,200	70,700
Other Real Estate, Non Covered	8,700	7,900
Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	4,077,013	3,286,228
Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	96,261	118,790
Non-acquired loans | Substandard and doubtful
Loans and Allowance for Loan Losses
Total loans	47,500	62,800
Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	47,430	62,786
Non-acquired loans | Doubtful
Loans and Allowance for Loan Losses
Total loans	22	22
Acquired non-credit impaired loans
Loans and Allowance for Loan Losses
Total loans	1,049,538	1,327,999
Commercial non-owner occupied real estate | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	889,756	697,811
Commercial non-owner occupied real estate | Construction and land development | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	401,979	364,221	299,951
Commercial non-owner occupied real estate | Construction and land development | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	382,167	337,641
Commercial non-owner occupied real estate | Construction and land development | Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	13,633	15,466
Commercial non-owner occupied real estate | Construction and land development | Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	6,179	11,114
Commercial non-owner occupied real estate | Construction and land development | Acquired non-credit impaired loans
Loans and Allowance for Loan Losses
Total loans	13,849	24,099
Commercial non-owner occupied real estate | Other commercial non-owner occupied real estate | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	487,777	333,590	291,171
Commercial non-owner occupied real estate | Other commercial non-owner occupied real estate | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	471,466	307,450
Commercial non-owner occupied real estate | Other commercial non-owner occupied real estate | Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	13,912	20,596
Commercial non-owner occupied real estate | Other commercial non-owner occupied real estate | Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	2,399	5,544
Commercial non-owner occupied real estate | Other commercial non-owner occupied real estate | Acquired non-credit impaired loans
Loans and Allowance for Loan Losses
Total loans	40,103	49,476
Consumer real estate | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	1,338,239	1,070,712
Consumer real estate | Consumer owner occupied | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	1,018,984	786,778	548,170
Consumer real estate | Consumer owner occupied | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	984,780	746,847
Consumer real estate | Consumer owner occupied | Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	17,777	22,129
Consumer real estate | Consumer owner occupied | Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	16,427	17,802
Consumer real estate | Consumer owner occupied | Acquired non-credit impaired loans
Loans and Allowance for Loan Losses
Total loans	518,107	646,375
Consumer real estate | Home equity loans | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	319,255	283,934	257,139
Consumer real estate | Home equity loans | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	304,744	269,844
Consumer real estate | Home equity loans | Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	8,171	8,047
Consumer real estate | Home equity loans | Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	6,318	6,021
Consumer real estate | Home equity loans | Non-acquired loans | Doubtful
Loans and Allowance for Loan Losses
Total loans	22	22
Consumer real estate | Home equity loans | Acquired non-credit impaired loans
Loans and Allowance for Loan Losses
Total loans	190,968	234,949
Consumer real estate | Other Consumer | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	46,573	45,222
Consumer real estate | Other Consumer | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	46,573	45,222
Commercial owner occupied real estate | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	1,033,398	907,913	833,513
Commercial owner occupied real estate | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	994,442	858,220
Commercial owner occupied real estate | Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	29,478	34,737
Commercial owner occupied real estate | Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	9,478	14,956
Commercial owner occupied real estate | Acquired non-credit impaired loans
Loans and Allowance for Loan Losses
Total loans	39,220	62,065
Commercial and industrial | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	503,808	405,923	321,824
Commercial and industrial | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	497,572	397,555
Commercial and industrial | Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	4,472	6,718
Commercial and industrial | Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	1,764	1,650
Commercial and industrial | Acquired non-credit impaired loans
Loans and Allowance for Loan Losses
Total loans	25,475	41,130
Other income producing property | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	175,848	150,928	143,204
Other income producing property | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	163,975	135,400
Other income producing property | Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	8,047	10,333
Other income producing property | Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	3,826	5,195
Other income producing property | Acquired non-credit impaired loans
Loans and Allowance for Loan Losses
Total loans	51,169	65,139
Consumer | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	233,104	189,317	136,410
Consumer | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	231,294	188,049
Consumer | Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	771	764
Consumer | Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	1,039	504
Consumer | Acquired non-credit impaired loans
Loans and Allowance for Loan Losses
Total loans	170,647	204,766
Consumer | All Consumer | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	1,617,916	1,305,251
Consumer | All Consumer | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	1,567,391	1,249,962
Consumer | All Consumer | Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	26,719	30,940
Consumer | All Consumer | Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	23,784	24,327
Consumer | All Consumer | Non-acquired loans | Doubtful
Loans and Allowance for Loan Losses
Total loans	22	22
Other Loans | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	46,573	45,222	$ 33,834
Commercial | Non-acquired loans
Loans and Allowance for Loan Losses
Total loans	2,602,810	2,162,575
Commercial | Non-acquired loans | Pass
Loans and Allowance for Loan Losses
Total loans	2,509,622	2,036,266
Commercial | Non-acquired loans | Special mention
Loans and Allowance for Loan Losses
Total loans	69,542	87,850
Commercial | Non-acquired loans | Substandard
Loans and Allowance for Loan Losses
Total loans	$ 23,646	$ 38,459