Goodwill and Other Intangibles Assets (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Finite-lived Intangible Assets [Roll Forward]
Balance at the beginning of period	$ 16,018
Amortization	3,315	3,538	4,088
Balance at the end of period	12,703	16,018
Core deposit intangibles
Finite-lived Intangible Assets [Roll Forward]
Balance at the beginning of period	10,373
Amortization	2,199
Balance at the end of period	8,174
Core deposit intangibles | Maximum
Goodwill and Other Intangible Assets
Intangible asset estimated period	10 years
Customer relationship intangibles
Finite-lived Intangible Assets [Roll Forward]
Balance at the beginning of period	5,645
Amortization	1,116
Balance at the end of period	$ 4,529
Customer relationship intangibles | Maximum
Goodwill and Other Intangible Assets
Intangible asset estimated period	10 years