Business Combinations, (Bay Bank and Trust Company) (Details) (USD $) Share data in Thousands, unless otherwise specified	6 Months Ended		0 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Mar. 16, 2012 Bay Bank and Trust Company [Member]	Jun. 30, 2012 Bay Bank and Trust Company [Member]	Mar. 31, 2012 Bay Bank and Trust Company [Member]	Jun. 30, 2012 Bay Bank and Trust Company [Member]
Business Acquisition [Line Items]
Age of acquired entity			76 years
Business acquisition, cost of acquired entity, cash paid			$ 10,000,000
Business acquisition, equity issued (in shares)			510
Business acquisition, equity issued, value assigned			12,000,000
Assets:
Cash and due from banks			88,154,000
Securities available for sale			26,369,000
Acquired noncovered loans			97,914,000
Premises and equipment, net			9,466,000
Identifiable intangible assets			7,017,000
Other real estate			2,569,000
Other assets			3,471,000
Total Assets	1,849,929,000	234,960,000	234,960,000
Liabilities:
Deposits			208,796,000
Other liabilities			526,000
Total Liabilities	1,821,066,000	209,322,000	209,322,000
Net assets acquired at fair value			25,638,000
Consideration paid to acquiree			22,003,000
Bargain purchase gain	0	3,635,000		881,000	2,800,000	3,635,000
Income taxes						0
Bargain purchase gain, net of taxes						3,635,000
Business acquisition, total transaction expenses					2,600,000
Business acquisition, severance expense					672,000
Business acquisition, contract termination and other expenses					$ 1,900,000
Amortization period of acquired intangible asset					10 years