Other Intangible Assets (Amortization Expense of Core Deposit Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Carrying amount	$ 15,388	$ 11,472
Amortization of intangible assets	3,969	3,615	3,609
Core deposit intangible assets [Member]
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Gross original amount	18,659	26,468
Accumulated amortization	6,749	18,589
Carrying amount	11,910	7,879
Amortization of intangible assets	$ 1,569	$ 1,527