Fair Value Disclosures - Assets, Liabilities and Off-balance Sheet Items Not Measured at Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Assets:
Held-to-maturity securities	$ 32,946	$ 41,061
Deposits:
Time deposits	360,192	454,406
Subordinated notes	49,450	49,377
Fair Value [Member]
Assets:
Cash and short-term interest-earning assets	93,190	60,799
Held-to-maturity securities	32,946	41,061
Loans held for sale	4,766	4,708
Net loans and leases held for investment	2,233,013	2,099,082
Mortgage servicing rights	6,785	8,047
Other real estate owned	3,131	1,276
Total assets	2,373,831	2,214,973
Deposits:
Demand and savings deposits, non-maturity	2,016,892	1,939,954
Time deposits	361,256	455,527
Total deposits	2,378,148	2,395,481
Short-term borrowings	259,971	22,302
Subordinated notes		50,375
Subordinated notes	50,250
Total liabilities	2,688,369	2,468,158
Off-Balance-Sheet:
Commitments to extend credit	(1,874)	(1,788)
Fair Value [Member] | Level 1 [Member]
Assets:
Cash and short-term interest-earning assets	93,190	60,799
Held-to-maturity securities	0	0
Loans held for sale	0	0
Net loans and leases held for investment	0	0
Mortgage servicing rights	0	0
Other real estate owned	0	0
Total assets	93,190	60,799
Deposits:
Demand and savings deposits, non-maturity	2,016,892	1,939,954
Time deposits	0	0
Total deposits	2,016,892	1,939,954
Short-term borrowings	0	0
Subordinated notes		0
Subordinated notes	0
Total liabilities	2,016,892	1,939,954
Off-Balance-Sheet:
Commitments to extend credit	0	0
Fair Value [Member] | Level 2 [Member]
Assets:
Cash and short-term interest-earning assets	0	0
Held-to-maturity securities	32,946	41,061
Loans held for sale	4,766	4,708
Net loans and leases held for investment	0	0
Mortgage servicing rights	0	0
Other real estate owned	3,131	1,276
Total assets	40,843	47,045
Deposits:
Demand and savings deposits, non-maturity	0	0
Time deposits	361,256	455,527
Total deposits	361,256	455,527
Short-term borrowings	259,971	22,302
Subordinated notes		50,375
Subordinated notes	50,250
Total liabilities	671,477	528,204
Off-Balance-Sheet:
Commitments to extend credit	(1,874)	(1,788)
Fair Value [Member] | Level 3 [Member]
Assets:
Cash and short-term interest-earning assets	0	0
Held-to-maturity securities	0	0
Loans held for sale	0	0
Net loans and leases held for investment	2,233,013	2,099,082
Mortgage servicing rights	6,785	8,047
Other real estate owned	0	0
Total assets	2,239,798	2,107,129
Deposits:
Demand and savings deposits, non-maturity	0	0
Time deposits	0	0
Total deposits	0	0
Short-term borrowings	0	0
Subordinated notes		0
Subordinated notes	0
Total liabilities	0	0
Off-Balance-Sheet:
Commitments to extend credit	0	0
Carrying Amount [Member]
Assets:
Cash and short-term interest-earning assets	93,190	60,799
Held-to-maturity securities	32,885	40,990
Loans held for sale	4,657	4,680
Net loans and leases held for investment	2,284,260	2,112,774
Mortgage servicing rights	5,896	5,877
Other real estate owned	3,131	1,276
Total assets	2,424,019	2,226,396
Deposits:
Demand and savings deposits, non-maturity	2,016,892	1,939,954
Time deposits	360,192	454,406
Total deposits	2,377,084	2,394,360
Short-term borrowings	260,216	24,211
Subordinated notes		49,377
Subordinated notes	49,450
Total liabilities	2,686,750	2,467,948
Off-Balance-Sheet:
Commitments to extend credit	$ 0	$ 0