Statements of Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011
Statements of Cash Flows [Abstract]
Income taxes paid	$ 37,551		$ 22,374
Interest expense paid on deposits and borrowings	24,197		33,907
Noncash transfers from loans to foreclosed properties	33,740	[1]	48,975	[1]
Transfer of long-term FHLB advance to short-term	0		1,900
Assets acquired in business combination	234,960		207,243
Liabilities assumed in business combination	$ 209,322		$ 228,236

[1] Includes transfers from covered loans to foreclosed properties.