Intangible Assets (Amortization Expense of Core Deposit Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Carrying amount	$ 14,354	$ 10,607	$ 14,354	$ 10,607	$ 15,388
Amortization of intangible assets			1,994	2,068
Core deposit intangible assets [Member]
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Gross original amount	18,659	26,468	18,659	26,468	18,659
Accumulated amortization	7,726	19,324	7,726	19,324	6,749
Carrying amount	10,933	7,144	10,933	7,144	11,910
Amortization of intangible assets	$ 484	$ 368	$ 977	$ 735