Goodwill, Core Deposit Premium and Other Intangible Assets (Changes in capitalized mortgage and commercial servicing rights) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Mortgage servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period	$ 30,314	$ 24,984
Originations	2,395	2,686
Amortization	(2,259)	(2,175)
Balance at end of period	30,450	25,495
Fair value of servicing rights	$ 38,944	$ 34,492	$ 40,900
Servicing rights, net to servicing portfolio (as a percent)	0.74%	0.71%
Commercial servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period	$ 4,611	$ 0
Purchased commercial servicing rights	190	4,255
Originations	195	132
Amortization	(536)	(215)
Balance at end of period	4,460	4,172
Fair value of servicing rights	$ 4,899	$ 4,429
Servicing rights, net to servicing portfolio (as a percent)	2.35%	2.87%