Acquisitions (Activity for Acquired Loans) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012
Activity for accretable yield includes contractually due interest of acquired loans
Balance at beginning of period	$ 49,390		$ 68,305
Additions (reductions)	(1,874)	[1]	4,564	[1]
Accretion recognized in interest income	(9,321)		(12,784)
Reclassification from nonaccretable difference	125		0
Balance at end of period	$ 38,320		$ 60,085

[1] Represents additions of estimated contractual interest expected to be collected from acquired loans being renewed or extended, less reductions in contractual interest resulting from the early payoff of acquired loans.