Statements of Cash Flows (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended					12 Months Ended		9 Months Ended	12 Months Ended		9 Months Ended	12 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2013 As Reported [Member]	Dec. 31, 2013 As Reported [Member]	Dec. 31, 2012 As Reported [Member]	Sep. 30, 2013 Adjustment [Member]	Dec. 31, 2013 Adjustment [Member]	Dec. 31, 2012 Adjustment [Member]	Sep. 30, 2013 As Adjusted [Member]	Dec. 31, 2013 As Adjusted [Member]	Dec. 31, 2012 As Adjusted [Member]
Statements of Cash Flows [Abstract]
Income taxes paid	$ 13,205		$ 14,220
Interest expense paid on deposits and borrowings	16,361		18,656
Noncash transfers from loans to foreclosed properties	30,671	[1]	34,226	[1]
Assets acquired in business combination	0		1,845,930
Liabilities assumed in business combination	0		1,821,066
Prior Period Adjustments [Line Items]
Net cash provided by operating activities	159,582		264,015		151,260	155,417	92,125	112,755	145,766	20,152	264,015	301,183	112,277
Net cash used in investing activities	(477,919)		(261,751)		(148,996)	(113,201)	193,891	(112,755)	(145,766)	(20,152)	(261,751)	(258,967)	173,739
Net cash provided by financing activities	210,073		101,942		101,942	72,056	(257,152)	0	0	0	101,942	72,056	(257,152)
(Decrease) Increase in cash and cash equivalents	(108,264)		104,206		104,206	114,272	28,864	0	0	0	104,206	114,272	28,864
Cash and cash equivalents at beginning of period	345,761		231,489		231,489	231,489	202,625	0	0	0	231,489	231,489	202,625
Cash and cash equivalents at end of period	$ 237,497		$ 335,695		$ 335,695	$ 345,761	$ 231,489	$ 0	$ 0	$ 0	$ 335,695	$ 345,761	$ 231,489

[1] Includes transfers from covered loans to covered other real estate.