Loans and Allowance for Loan Losses (Impaired Loans) (Details) - USD ($) $ in Thousands		9 Months Ended		12 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Interest lost on nonaccrual loans		$ 1,200	$ 1,700
Loans on nonaccrual status		19,500		$ 25,300
Impaired loans, no individually reviewed for impairment		4,124		4,967
Impaired loans, individually reviewed, with no impairment		24,013		26,631
Impaired loans, individually reviewed, with impairment		3,448		7,851
Total impaired loans, excluding purchased impaired	[1]	31,585		39,449
Purchased impaired loans with subsequent deterioration		89,292		118,701
Purchased impaired loans with no subsequent deterioration		3,385		4,141
Impaired loan, individually reviewed, with impairment, associated reserves	[1]	344		418
Purchased impaired loans with subsequent deterioration		3,190		3,237
Impaired financing receivable, including deteriorated loans purchased, related allowance		3,534		3,655
Impaired financing receivable, simple average balance		$ 35,517		$ 43,446

[1] * Included at September 30, 2015 and December 31, 2014 were $13.2 million and $14.1 million, respectively, in restructured and performing loans.