Goodwill, Core Deposit Premium and Other Intangible Assets (Changes in capitalized mortgage servicing rights) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Mortgage servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period	$ 24,984	$ 21,788
Originations	2,686	1,435
Amortization	(2,175)	(1,079)
Balance at end of period	25,495	22,144
Servicing asset at fair value	34,492	32,032	34,200
Mortgage servicing rights, net to servicing portfolio	0.71%	0.71%
Commercial servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period	0	0
Acquired	4,255	0
Originations	132	0
Amortization	(215)	0
Balance at end of period	4,172	0
Servicing asset at fair value	$ 4,400