Fair Value Measurements - (Details 7) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Financial assets
Securities held to maturity	$ 476,752	$ 430,163
Securities available for sale	662,801	553,584
Mortgage loans held for sale	317,681	25,628
Loans covered under loss-share agreements	100,839	143,041
FDIC loss-share indemnification asset	8,044	12,516
Mortgage servicing rights	28,268	11,662
Level 1
Financial assets
Cash and cash equivalents	203,849	161,583
Securities held to maturity	0	0
Securities available for sale	0	0
Mortgage loans held for sale	0	0
Loans covered under loss-share agreements	0	0
Loans not covered under loss-share agreements, net	0	0
FDIC loss-share indemnification asset	0	0
Mortgage servicing rights	0	0
Derivative instruments	0	0
Financial liabilities
Deposits	4,200,398	3,532,266
Short-term borrowings	402,122	32,403
Federal Home Loan Bank advances	0	0
Junior subordinated debentures	0	0
Derivative instruments	0	0
Level 2
Financial assets
Cash and cash equivalents	0	0
Securities held to maturity	490,233	442,488
Securities available for sale	643,911	533,828
Mortgage loans held for sale	317,681	25,628
Loans covered under loss-share agreements	0	0
Loans not covered under loss-share agreements, net	0	0
FDIC loss-share indemnification asset	0	0
Mortgage servicing rights	0	0
Derivative instruments	12,575	3,731
Financial liabilities
Deposits	1,546,930	1,309,421
Short-term borrowings	0	0
Federal Home Loan Bank advances	58,439	92,532
Junior subordinated debentures	79,053	80,971
Derivative instruments	12,462	6,293
Level 3
Financial assets
Cash and cash equivalents	0	0
Securities held to maturity	0	0
Securities available for sale	18,890	19,756
Mortgage loans held for sale	0	0
Loans covered under loss-share agreements	134,962	143,487
Loans not covered under loss-share agreements, net	5,100,022	3,751,727
FDIC loss-share indemnification asset	8,044	12,516
Mortgage servicing rights	28,559	12,378
Derivative instruments	0	0
Financial liabilities
Deposits	0	0
Short-term borrowings	0	0
Federal Home Loan Bank advances	0	0
Junior subordinated debentures	0	0
Derivative instruments	0	0
Carrying Value
Financial assets
Cash and cash equivalents	203,849	161,583
Securities held to maturity	476,752	430,163
Securities available for sale	662,801	553,584
Mortgage loans held for sale	317,681	25,628
Loans covered under loss-share agreements	100,839	143,041
Loans not covered under loss-share agreements, net	5,135,070	3,844,833
FDIC loss-share indemnification asset	8,044	12,516
Mortgage servicing rights	28,268	11,662
Derivative instruments	12,575	3,731
Financial liabilities
Deposits	6,234,561	4,838,418
Short-term borrowings	402,122	32,403
Federal Home Loan Bank advances	54,456	61,611
Junior subordinated debentures	94,958	94,574
Derivative instruments	12,462	6,293
Fair Value
Financial assets
Cash and cash equivalents	203,849	161,583
Securities held to maturity	490,233	442,488
Securities available for sale	662,801	553,584
Mortgage loans held for sale	317,681	25,628
Loans covered under loss-share agreements	134,962	143,487
Loans not covered under loss-share agreements, net	5,100,022	3,751,727
FDIC loss-share indemnification asset	8,044	12,516
Mortgage servicing rights	28,559	12,378
Derivative instruments	12,575	3,731
Financial liabilities
Deposits	5,747,328	4,841,687
Short-term borrowings	402,122	32,403
Federal Home Loan Bank advances	58,439	92,532
Junior subordinated debentures	79,053	80,971
Derivative instruments	$ 12,462	$ 6,293