Loans and Allowance for Loan Losses (Impaired Loans) (Details) (USD $)	3 Months Ended			12 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Interest lost on nonaccrual loans	$ 800,000		$ 1,000,000
Loans on nonaccrual status	20,300,000			25,300,000
Impaired loans, no individually reviewed for impairment	4,603,000			4,967,000
Impaired loans, individually reviewed, with no impairment	22,134,000			26,631,000
Impaired loans, individually reviewed, with impairment	7,550,000			7,851,000
Total impaired loans, excluding purchased impaired	34,287,000	[1]		39,449,000	[1]
Purchased impaired loans with subsequent deterioration	105,662,000			118,701,000
Purchased impaired loans with no subsequent deterioration	3,600,000			4,141,000
Impaired loan, individually reviewed, with impairment, associated reserves	364,000	[1]		418,000	[1]
Purchased impaired loans with subsequent deterioration, associated reserves	3,194,000			3,237,000
Impaired financing receivable, including deteriorated loans purchased, related allowance	3,558,000			3,655,000
Impaired financing receivable, simple average balance	36,868,000			43,446,000
Restructured loans	18,200,000			19,400,000
Performing [Member]
Financing Receivable, Impaired [Line Items]
Restructured loans	$ 14,000,000			$ 14,100,000

[1] * Included at March 31, 2015 and December 31, 2014 were $14.0 million and $14.1 million, respectively, in restructured and performing loans.