Loans (Details 10) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance Contractual Amount Receivable				$ 1,613,496					$ 1,613,496
Ending Balance Contractual Amount Receivable	1,686,319				1,613,496				1,686,319	1,613,496
Additional provision for loan loss Recorded Loan Receivable	(162)	(406)	(446)	(103)	(475)	(476)	(448)	(425)	(1,117)	(1,824)	(10,924)
Loans and Debt Securities Acquired With Deteriorated Credit Quality [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning Balance Contractual Amount Receivable				503				855	503	855	2,206
Principal payments received Contractual Amount Receivable									(90)	(108)	(697)
Loans charged off Contractual Amount Receivable									0	(41)	(487)
Additional provision for loan loss Contractual Amount Receivable									0	(203)	(167)
Loan accretion recorded Contractual Amount Receivable									0	0	0
Ending Balance Contractual Amount Receivable	413				503				413	503	855
Beginning Balance Impairment Discount				273				343	273	343	1,003
Principal payments received Impairment Discount									0	0	0
Loans charged off Impairment Discount									0	(41)	(487)
Additional provision for loan loss Impairment Discount									0	0	0
Loan accretion recorded Impairment Discount									(46)	(29)	(173)
Ending Balance Impairment Discount	227				273				227	273	343
Beginning Balance Recorded Loan Receivable				230				512	230	512	1,203
Principal payments received Recorded Loan Receivable									(90)	(108)	(697)
Loans charged off Recorded Loan Receivable									0	0	0
Additional provision for loan loss Recorded Loan Receivable									0	(203)	(167)
Loan accretion recorded Recorded Loan Receivable									46	29	173
Ending Balance Recorded Loan Receivable	$ 186				$ 230				$ 186	$ 230	$ 512