Goodwill and Other Intangibles Assets (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Goodwill and Other Intangible Assets
Net carrying amount	$ 12,703	$ 16,018
Estimated amortization expense:
Net carrying amount	12,703	16,018
Core deposit intangibles
Goodwill and Other Intangible Assets
Gross carrying amount	34,836
Accumulated amortization	26,662
Net carrying amount	8,174	10,373
Estimated amortization expense:
2013	2,050
2014	1,870
2015	1,720
2016	1,644
2017	890
Net carrying amount	8,174	10,373
Customer relationship intangibles
Goodwill and Other Intangible Assets
Gross carrying amount	11,320
Accumulated amortization	6,791
Net carrying amount	4,529	5,645
Estimated amortization expense:
2013	1,082
2014	1,014
2015	973
2016	929
2017	531
Net carrying amount	$ 4,529	$ 5,645