Loans and Allowance for Loan Losses, Financing Receivables Past Due (Details) - USD ($) $ in Thousands		Sep. 30, 2015		Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		$ 21,830		$ 18,330
Nonaccrual	[1]	30,049		16,705
Current and accruing		6,284,110		4,554,992
Total Loans		6,335,989		4,590,027
Currently performing impaired loans		19,600		10,200
30-89 Days Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		16,466		18,007
90 Days or More Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		5,364	[2]	323
Commercial Real Estate Owner Occupied [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		585		0
Nonaccrual	[1]	4,656		4,313
Current and accruing		1,119,652		760,207
Total Loans		1,124,893		764,520
Commercial Real Estate Owner Occupied [Member] | 30-89 Days Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		362		0
Commercial Real Estate Owner Occupied [Member] | 90 Days or More Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		223	[2]	0
Commercial Real Estate All Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		1,275		2,232
Nonaccrual	[1]	2,576		0
Current and accruing		1,063,407		777,339
Total Loans		1,067,258		779,571
Commercial Real Estate All Other [Member] | 30-89 Days Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		886		2,232
Commercial Real Estate All Other [Member] | 90 Days or More Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		389	[2]	0
Consumer Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		5,223		2,537
Nonaccrual	[1]	9,421		4,458
Current and accruing		1,029,632		714,163
Total Loans		1,044,276		721,158
Consumer Real Estate - Mortgage [Member] | 30-89 Days Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		3,185		2,391
Consumer Real Estate - Mortgage [Member] | 90 Days or More Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		2,038	[2]	146
Construction and Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		2,912		421
Nonaccrual	[1]	6,498		5,173
Current and accruing		665,516		316,872
Total Loans		674,926		322,466
Construction and Land Development [Member] | 30-89 Days Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		573		421
Construction and Land Development [Member] | 90 Days or More Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		2,339	[2]	0
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		2,879		3,436
Nonaccrual	[1]	1,122		1,609
Current and accruing		2,174,534		1,779,684
Total Loans		2,178,535		1,784,729
Commercial and Industrial [Member] | 30-89 Days Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		2,765		3,431
Commercial and Industrial [Member] | 90 Days or More Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		114	[2]	5
Consumer and Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		8,956		9,704
Nonaccrual	[1]	5,776		1,152
Current and accruing		231,369		206,727
Total Loans		246,101		217,583
Consumer and Other [Member] | 30-89 Days Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		8,695		9,532
Consumer and Other [Member] | 90 Days or More Past Due and Performing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due and accruing		$ 261	[2]	$ 172

[1] Approximately $19.6 million and $10.2 million of nonaccrual loans as of September 30, 2015 and December 31, 2014, respectively, were performing pursuant to their contractual terms at those dates.

[2] Approximately $1.3 million of the 90 days or more past due and accruing were obtained from our acquisitions with CapitalMark and Magna.