Loans and Allowance for Loan Losses - TDRs and pre and post-modification recorded investment (Details 8) (Loans Receivable, USD $) In Thousands, unless otherwise specified	Jun. 30, 2013 Contract	Dec. 31, 2012 Contract	Jun. 30, 2012 Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts	328	388	377
Pre-Modification Outstanding Recorded Investment	$ 92,264	$ 172,727	$ 177,129
Post-Modification Outstanding Recorded Investment	84,877	160,763	167,613
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of Contracts	110	117	110
Pre-Modification Outstanding Recorded Investment	17,772	20,323	17,613
Post-Modification Outstanding Recorded Investment	16,381	19,296	16,950
Residential construction
Financing Receivable, Modifications [Line Items]
Number of Contracts	51	67	72
Pre-Modification Outstanding Recorded Investment	11,895	25,822	25,123
Post-Modification Outstanding Recorded Investment	9,908	23,786	22,178
Consumer installment
Financing Receivable, Modifications [Line Items]
Number of Contracts	42	51	47
Pre-Modification Outstanding Recorded Investment	447	1,292	521
Post-Modification Outstanding Recorded Investment	337	1,282	511
Commercial
Financing Receivable, Modifications [Line Items]
Number of Contracts	125	153	148
Pre-Modification Outstanding Recorded Investment	62,150	125,290	133,872
Post-Modification Outstanding Recorded Investment	58,251	116,399	127,974
Commercial | Commercial (secured by real estate)
Financing Receivable, Modifications [Line Items]
Number of Contracts	77	96	96
Pre-Modification Outstanding Recorded Investment	45,874	80,261	87,104
Post-Modification Outstanding Recorded Investment	42,366	75,340	82,325
Commercial | Commercial & industrial
Financing Receivable, Modifications [Line Items]
Number of Contracts	34	32	29
Pre-Modification Outstanding Recorded Investment	3,091	7,492	3,972
Post-Modification Outstanding Recorded Investment	2,929	7,250	3,972
Commercial | Commercial construction
Financing Receivable, Modifications [Line Items]
Number of Contracts	14	25	23
Pre-Modification Outstanding Recorded Investment	13,185	37,537	42,796
Post-Modification Outstanding Recorded Investment	$ 12,956	$ 33,809	$ 41,677