Goodwill, Core Deposit Premium and Other Intangible Assets (Estimated future amortization expense for amortizable intangible assets) (Details) $ in Thousands	Sep. 30, 2016 USD ($)
Future amortization expense for amortizable intangible assets [Line Items]
Three months ending December 31, 2016	$ 4,416
Year ending December 31,
2017	12,576
2018	10,962
2019	9,269
2020	7,619
2021	6,075
Thereafter	8,911
Total	59,828
Core deposit intangibles
Future amortization expense for amortizable intangible assets [Line Items]
Three months ending December 31, 2016	1,206
Year ending December 31,
2017	4,409
2018	3,900
2019	3,418
2020	2,975
2021	2,457
Thereafter	5,226
Total	23,591
Mortgage servicing rights
Future amortization expense for amortizable intangible assets [Line Items]
Three months ending December 31, 2016	2,968
Year ending December 31,
2017	7,219
2018	6,187
2019	5,156
2020	4,125
2021	3,094
Thereafter	3,093
Total	31,842
Customer relationship intangible
Future amortization expense for amortizable intangible assets [Line Items]
Three months ending December 31, 2016	10
Year ending December 31,
2017	40
2018	39
2019	38
2020	37
2021	35
Thereafter	132
Total	331
Commercial servicing rights
Future amortization expense for amortizable intangible assets [Line Items]
Three months ending December 31, 2016	232
Year ending December 31,
2017	908
2018	836
2019	657
2020	482
2021	489
Thereafter	460
Total	$ 4,064