Acquisition of Bank of Granite Corporation (Fair Value of Asset and Liabilities Assumed) (Details) (Granite Corp. [Member], USD $) In Thousands, unless otherwise specified	Oct. 21, 2011
Granite Corp. [Member]
Assets acquired:
Cash and cash equivalents	$ 99,126
Investment securities	186,361
Loans, net	393,653
Premises and equipment, net	9,778
Other real estate owned	18,136
Bank-owned life insurance	4,432
Core deposit intangible	4,900
Other assets	7,766
Total assets acquired	724,152
Liabilities assumed:
Deposits	719,443
Other	3,990
Total liabilities assumed	723,433
Total shareholders’ equity	0
Total liabilities assumed and shareholders’ equity	723,433
Contributed capital	4,924
Total liabilities assumed and contributed capital	728,357
Goodwill (excess of liabilities assumed and contributed capital over assets acquired)	$ 4,205