Loans - Age Analysis of Loans (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
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	$ 19,891	$ 20,461
90 Days or More Past Due	2,651	1,169
Total loans past due and still accruing	22,542	21,630
Nonaccrual	62,619	76,806
Purchased Credit Impaired	20,506	25,188
Current	3,017,688	2,974,596
Loans held for investment	3,123,355	3,098,220	$ 3,189,436
Originated
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	13,756	11,373
90 Days or More Past Due	959	1,169
Total loans past due and still accruing	14,715	12,542
Nonaccrual	41,980	39,763
Current	2,420,059	2,249,623
Loans held for investment	2,476,754	2,301,928	2,215,064
Acquired
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	6,135	9,088
90 Days or More Past Due	1,692
Total loans past due and still accruing	7,827	9,088
Nonaccrual	20,639	37,043
Purchased Credit Impaired	20,506	25,188
Current	597,629	724,973
Loans held for investment	646,601	796,292	974,372
Commercial & Industrial
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans held for investment	1,144,332	1,053,925
Commercial & Industrial | Originated
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	1,408	1,515
90 Days or More Past Due		1,106
Total loans past due and still accruing	1,408	2,621
Nonaccrual	37,909	36,331
Current	1,013,037	865,379
Loans held for investment	1,052,354	904,331	905,683
Commercial & Industrial | Acquired
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	4,256	2,854
90 Days or More Past Due	24
Total loans past due and still accruing	4,280	2,854
Nonaccrual	11,595	23,424
Purchased Credit Impaired	2,288	4,506
Current	73,815	118,810
Loans held for investment	91,978	149,594	222,858
Owner occupied commercial real estate
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans held for investment	407,317	394,210
Owner occupied commercial real estate | Originated
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	504	1,941
Total loans past due and still accruing	504	1,941
Current	306,010	262,935
Loans held for investment	306,514	264,876	222,762
Owner occupied commercial real estate | Acquired
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	586	223
Total loans past due and still accruing	586	223
Nonaccrual	6,958	8,942
Purchased Credit Impaired	5,131	5,339
Current	88,128	114,830
Loans held for investment	100,803	129,334	143,825
Commercial real estate
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans held for investment	1,109,237	1,143,751
Commercial real estate | Originated
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	4,952	1,612
90 Days or More Past Due	393
Total loans past due and still accruing	5,345	1,612
Nonaccrual	1,979	2,059
Current	800,017	812,358
Loans held for investment	807,341	816,029	710,431
Commercial real estate | Acquired
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	128	2,529
90 Days or More Past Due	56
Total loans past due and still accruing	184	2,529
Nonaccrual		2,002
Purchased Credit Impaired	10,607	10,807
Current	291,105	312,384
Loans held for investment	301,896	327,722	368,003
Construction, land & land development
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans held for investment	201,992	249,704
Construction, land & land development | Originated
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	1,974	4,375
90 Days or More Past Due	195
Total loans past due and still accruing	2,169	4,375
Current	151,353	175,624
Loans held for investment	153,522	179,999	240,098
Construction, land & land development | Acquired
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	1,090	488
90 Days or More Past Due	612
Total loans past due and still accruing	1,702	488
Nonaccrual	1,467	978
Purchased Credit Impaired	18	1,819
Current	45,283	66,420
Loans held for investment	48,470	69,705	94,827
Residential mortgage
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans held for investment	239,834	245,191
Residential mortgage | Originated
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	4,763	1,791
90 Days or More Past Due	371	63
Total loans past due and still accruing	5,134	1,854
Nonaccrual	2,038	1,254
Current	130,746	124,337
Loans held for investment	137,918	127,445	128,168
Residential mortgage | Acquired
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	75	2,768
90 Days or More Past Due	1,000
Total loans past due and still accruing	1,075	2,768
Nonaccrual	403	1,692
Purchased Credit Impaired	2,462	2,717
Current	97,976	110,569
Loans held for investment	101,916	117,746	142,169
Consumer and other
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans held for investment	20,643	11,439
Consumer and other | Originated
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due	155	139
Total loans past due and still accruing	155	139
Nonaccrual	54	119
Current	18,896	8,990
Loans held for investment	19,105	9,248	7,922
Consumer and other | Acquired
Financing Receivable, Recorded Investment, Aging [Abstract]
30-89 Past Due		226
Total loans past due and still accruing		226
Nonaccrual	216	5
Current	1,322	1,960
Loans held for investment	$ 1,538	$ 2,191	$ 2,690