Goodwill, Core Deposit Premium and Other Intangible Assets (Changes in capitalized mortgage and commercial servicing rights) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Servicing Asset at Fair Value, Amount [Roll Forward]
Sale of mortgage servicing rights	$ (6,900)
Valuation allowance on commercial servicing rights	5	$ 5	$ 29	$ (41)
Mortgage Servicing Rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period			32,088	30,314
Originations			5,778	9,323
Amortization			(7,184)	(7,795)
Sale of mortgage servicing rights			(6,940)	0
Balance at end of period	23,742	31,842	23,742	31,842
Fair value of servicing rights	35,000	38,127	$ 35,000	$ 38,127	$ 45,200
Commercial servicing rights, net to servicing portfolio			0.67%	0.75%
Commercial servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period			$ 3,690	$ 4,611
Purchased commercial servicing rights			0	190
Originations			215	533
Amortization			(1,077)	(1,229)
Valuation allowance on commercial servicing rights			29	(41)
Balance at end of period	2,857	4,064	2,857	4,064
Fair value of servicing rights	$ 3,458	$ 4,397	$ 3,458	$ 4,397	$ 4,100
Commercial servicing rights, net to servicing portfolio			1.98%	2.38%