Goodwill, Core Deposit Premium and Other Intangible Assets (Changes in capitalized mortgage and commercial servicing rights) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Mortgage servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at January 1	$ 24,984	$ 21,788
Originations	11,062	5,955
Amortization	(6,446)	(3,778)
Balance at September 30	29,600	23,965
Fair value of servicing rights	$ 40,166	$ 33,260	$ 34,200
Servicing rights, net to servicing portfolio (as a percent)	0.75%	0.71%
Commercial servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at January 1	$ 0	$ 0
Purchased commercial servicing rights	4,255	0
Originations	704	0
Amortization	(802)	0
Balance at September 30	4,157	0
Fair value of servicing rights	$ 4,412	$ 0
Servicing rights, net to servicing portfolio (as a percent)	2.33%	0.00%