Goodwill and Intangible Assets (Estimated Future Amortization Expense of Core Deposit Intangibles) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Future Amortization Expense For Core Deposit Intangibles
2013	$ 2,936
2014	3,397
2015	2,645
2016	2,183
2017	$ 1,627