Loans - Age Analysis of Loans (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual status, days past due	90 days
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	$ 35,009	$ 29,871
90 Days or More Past Due	14,320	52
Total loans past due and still accruing	49,329	29,923
Nonaccrual	67,481	39,005
Purchased Credit Impaired	39,326	46,174
Current	3,033,300	3,015,567
Loans held for investment	3,189,436	3,130,669	$ 1,894,742
Originated [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	13,427	13,994
90 Days or More Past Due	2,885	45
Total loans past due and still accruing	16,312	14,039
Nonaccrual	59,532	35,703
Current	2,139,220	1,883,815
Loans held for investment	2,215,064	1,933,557
Acquired [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	21,582	15,877
90 Days or More Past Due	11,435	7
Total loans past due and still accruing	33,017	15,884
Nonaccrual	7,949	3,302
Purchased Credit Impaired	39,326	46,174
Current	894,080	1,131,752
Loans held for investment	974,372	1,197,112
Commercial & Industrial [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Purchased Credit Impaired	8,281	13,905
Loans held for investment	1,128,541	1,206,452	795,483
Commercial & Industrial [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	6,382	2,064
90 Days or More Past Due	298	25
Total loans past due and still accruing	6,680	2,089
Nonaccrual	58,173	34,205
Current	840,830	813,754
Loans held for investment	905,683	850,048
Commercial & Industrial [Member] | Acquired [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	17,992	10,908
90 Days or More Past Due	9,978
Total loans past due and still accruing	27,970	10,908
Nonaccrual	2,327	420
Purchased Credit Impaired	8,281	13,905
Current	184,280	331,171
Loans held for investment	222,858	356,404
Owner occupied commercial real estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Purchased Credit Impaired	6,605	7,149
Loans held for investment	366,587	353,889	176,453
Owner occupied commercial real estate [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	1,454	9,158
90 Days or More Past Due	1,737
Total loans past due and still accruing	3,191	9,158
Nonaccrual	778	829
Current	218,793	178,921
Loans held for investment	222,762	188,908
Owner occupied commercial real estate [Member] | Acquired [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	1,991	741
Total loans past due and still accruing	1,991	741
Nonaccrual	1,360
Purchased Credit Impaired	6,605	7,149
Current	133,869	157,091
Loans held for investment	143,825	164,981
Commercial real estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Purchased Credit Impaired	12,072	12,288
Loans held for investment	1,078,434	904,115	383,863
Commercial real estate [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	2,375	1,108
Total loans past due and still accruing	2,375	1,108
Current	708,056	520,779
Loans held for investment	710,431	521,887
Commercial real estate [Member] | Acquired [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	1,107
90 Days or More Past Due	1,026
Total loans past due and still accruing	2,133
Nonaccrual	2,060	1,590
Purchased Credit Impaired	12,072	12,288
Current	351,738	368,350
Loans held for investment	368,003	382,228
Construction, land & land development [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Purchased Credit Impaired	8,345	8,681
Loans held for investment	334,925	358,813	290,469
Construction, land & land development [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	1,176	181
90 Days or More Past Due	846
Total loans past due and still accruing	2,022	181
Nonaccrual		472
Current	238,076	241,958
Loans held for investment	240,098	242,611
Construction, land & land development [Member] | Acquired [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	177	111
90 Days or More Past Due	358
Total loans past due and still accruing	535	111
Purchased Credit Impaired	8,345	8,681
Current	85,947	107,410
Loans held for investment	94,827	116,202
Residential mortgage [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Purchased Credit Impaired	4,023	4,151
Loans held for investment	270,337	293,483	234,026
Residential mortgage [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	1,887	890
Total loans past due and still accruing	1,887	890
Nonaccrual	581	197
Current	125,700	119,173
Loans held for investment	128,168	120,260
Residential mortgage [Member] | Acquired [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	251	4,065
90 Days or More Past Due	73	6
Total loans past due and still accruing	324	4,071
Nonaccrual	2,200	1,292
Purchased Credit Impaired	4,023	4,151
Current	135,622	163,709
Loans held for investment	142,169	173,223
Consumer and other [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans held for investment	10,612	13,917	$ 14,448
Consumer and other [Member] | Originated [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	153	593
90 Days or More Past Due	4	20
Total loans past due and still accruing	157	613
Current	7,765	9,230
Loans held for investment	7,922	9,843
Consumer and other [Member] | Acquired [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	64	52
90 Days or More Past Due		1
Total loans past due and still accruing	64	53
Nonaccrual	2
Current	2,624	4,021
Loans held for investment	$ 2,690	$ 4,074