Fair Value (Details 4) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Dec. 31, 2012
Carrying amount and estimated fair value of financial instruments
Securities available-for-sale	$ 900,110		$ 914,560
Restricted stock	21,075		21,057
FDIC Indemnification Asset	375	420	1,055	2,632
Accrued interest receivable	12,100		11,554
Deposits	(2,451,952)		(2,458,791)
Level 1
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	22,198		22,455
Federal funds sold	0		0
Securities available-for-sale	0		0
Loans, net	0		0
FDIC Indemnification Asset	0		0
Accrued interest receivable	0		0
Deposits	0		0
Short-term borrowings	0		0
Federal Home Loan Bank advances	0		0
Accrued interest payable	0		0
Level 2
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	74,800		48,578
Federal funds sold	14,980		4,276
Securities available-for-sale	877,351		900,991
Loans, net	0		0
FDIC Indemnification Asset	375		1,055
Accrued interest receivable	3,598		3,279
Deposits	(2,451,389)		(2,460,197)
Short-term borrowings	(59,031)		(59,592)
Federal Home Loan Bank advances	(88,546)		(60,258)
Accrued interest payable	(495)		(750)
Level 3
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	0		0
Federal funds sold	0		0
Securities available-for-sale	22,759		13,569
Loans, net	1,825,140		1,816,726
FDIC Indemnification Asset	0		0
Accrued interest receivable	8,502		8,275
Deposits	0		0
Short-term borrowings	0		0
Federal Home Loan Bank advances	0		0
Accrued interest payable	0		0
Carrying Value
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	96,998		71,033
Federal funds sold	14,980		4,276
Securities available-for-sale	900,110		914,560
Restricted stock	21,075		21,057
Loans, net	1,793,818		1,771,360
FDIC Indemnification Asset	375		1,055
Accrued interest receivable	12,100		11,554
Deposits	(2,451,952)		(2,458,791)
Short-term borrowings	(59,031)		(59,592)
Federal Home Loan Bank advances	(87,961)		(58,288)
Accrued interest payable	(495)		(750)
Fair Value
Carrying amount and estimated fair value of financial instruments
Cash and due from banks	96,998		71,033
Federal funds sold	14,980		4,276
Securities available-for-sale	900,110		914,560
Loans, net	1,825,140		1,816,726
FDIC Indemnification Asset	375		1,055
Accrued interest receivable	12,100		11,554
Deposits	(2,451,389)		(2,460,197)
Short-term borrowings	(59,031)		(59,592)
Federal Home Loan Bank advances	(88,546)		(60,258)
Accrued interest payable	$ (495)		$ (750)