Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		9 Months Ended		12 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Investment securities available for sale [Abstract]
U.S. Treasury Securities		$ 9,999
U.S. government agency securities		144,803		$ 113,456
Mortgage-backed securities		590,971		455,839
State and municipal securities		163,494		138,578
Agency- backed securities		50,891		13,018
Corporate notes and other		12,137		11,164
Total investment securities available-for-sale		972,295		732,055
Other investments		7,845		8,004
Other assets		18,419		15,987
Total assets at fair value		998,559		756,046
Liabilities at fair value [Abstract]
Other liabilities		20,132		15,981
Total liabilities at fair value		20,132		15,981
Assets and liabilities measured at fair value on a nonrecurring basis [Abstract]
Other real estate owned		4,773		11,186
Nonperforming loans, net	[1]	27,900		15,551
Total		32,673		26,737
Gain (losses) on Other real estate owned		(18)		(509)
Gain (losses) on Impaired loans, net	[1]	(567)		(1,032)
Total gains (losses)		(585)		(1,541)
Other Liabilities [Member]
Assets measured on recurring basis, unobservable input reconciliation, calculation [Roll Forward]
Fair value, January 1		0	$ 0	0
Total net realized (losses) gains included in income		0	0
Change in unrealized gains/losses included in other comprehensive income for assets and liabilities still held at March 31		0	0
Purchases		0	0
Issuances		0	0
Settlements		0	0
Transfers out of Level 3		0	0
Fair value, March 31		0	0	0
Total net realized (losses) gains included in income related to financial assets and liabilities still on the consolidated balance sheet at March 31		0	0
Quoted Market Prices in an Active Market (Level 1) [Member]
Assets and liabilities measured at fair value on a nonrecurring basis [Abstract]
Other real estate owned		0		0
Nonperforming loans, net	[1]	0		0
Total		0		0
Models with Significant Observable Market Parameters (Level 2) [Member]
Assets and liabilities measured at fair value on a nonrecurring basis [Abstract]
Other real estate owned		0		0
Nonperforming loans, net	[1]	0		0
Total		0		0
Models with Significant Unobservable Market Parameters (Level 3) [Member]
Assets and liabilities measured at fair value on a nonrecurring basis [Abstract]
Other real estate owned		4,773		11,186
Nonperforming loans, net	[1]	27,900		15,551
Total		32,673		26,737
Recurring [Member] | Quoted Market Prices in an Active Market (Level 1) [Member]
Investment securities available for sale [Abstract]
U.S. Treasury Securities		9,999
U.S. government agency securities		0		0
Mortgage-backed securities		0		0
State and municipal securities		0		0
Agency- backed securities		0		0
Corporate notes and other		0		0
Total investment securities available-for-sale		9,999		0
Other investments		0		0
Other assets		0		0
Total assets at fair value		9,999		0
Liabilities at fair value [Abstract]
Other liabilities		0		0
Total liabilities at fair value		0		0
Recurring [Member] | Models with Significant Observable Market Parameters (Level 2) [Member]
Investment securities available for sale [Abstract]
U.S. Treasury Securities		0
U.S. government agency securities		144,803		113,456
Mortgage-backed securities		590,971		455,839
State and municipal securities		163,494		138,578
Agency- backed securities		50,891		13,018
Corporate notes and other		12,137		11,164
Total investment securities available-for-sale		962,296		732,055
Other investments		0		0
Other assets		18,419		15,987
Total assets at fair value		980,715		748,042
Liabilities at fair value [Abstract]
Other liabilities		20,132		15,981
Total liabilities at fair value		20,132		15,981
Recurring [Member] | Models with Significant Unobservable Market Parameters (Level 3) [Member]
Investment securities available for sale [Abstract]
U.S. Treasury Securities		0
U.S. government agency securities		0		0
Mortgage-backed securities		0		0
State and municipal securities		0		0
Agency- backed securities		0		0
Corporate notes and other		0		0
Total investment securities available-for-sale		0		0
Other investments		7,845		8,004
Other assets		0		0
Total assets at fair value		7,845		8,004
Liabilities at fair value [Abstract]
Other liabilities		0		0
Total liabilities at fair value		0		0
Other Assets [Member]
Assets measured on recurring basis, unobservable input reconciliation, calculation [Roll Forward]
Fair value, January 1		8,004	6,701	6,701
Total net realized (losses) gains included in income		(243)	406
Change in unrealized gains/losses included in other comprehensive income for assets and liabilities still held at March 31		0	0
Purchases		708	357
Issuances		0	0
Settlements		(624)	0
Transfers out of Level 3		0	0
Fair value, March 31		7,845	7,464	$ 8,004
Total net realized (losses) gains included in income related to financial assets and liabilities still on the consolidated balance sheet at March 31		$ (243)	$ 406

[1] Amount is net of a valuation allowance of $2.1 million at September 30, 2015 and $1.2 million at December 31, 2014, respectively, as required by ASC 310-10, "Receivables."