Goodwill, Core Deposit Premium and Other Intangible Assets (Estimated future amortization expense for amortizable intangible assets) (Details) $ in Thousands	Jun. 30, 2017 USD ($)
Future amortization expense for amortizable intangible assets [Line Items]
Six months ending December 31, 2017	$ 7,723
Year ending December 31,
2018	11,718
2019	10,095
2020	8,510
2021	6,943
2022	5,074
Thereafter	7,523
Total	57,586
Core deposit intangibles
Future amortization expense for amortizable intangible assets [Line Items]
Six months ending December 31, 2017	2,369
Year ending December 31,
2018	4,261
2019	3,741
2020	3,264
2021	2,716
2022	1,876
Thereafter	4,323
Total	22,550
Customer relationship intangibles
Future amortization expense for amortizable intangible assets [Line Items]
Six months ending December 31, 2017	20
Year ending December 31,
2018	39
2019	38
2020	36
2021	35
2022	34
Thereafter	98
Total	300
Mortgage servicing rights
Future amortization expense for amortizable intangible assets [Line Items]
Six months ending December 31, 2017	4,937
Year ending December 31,
2018	6,674
2019	5,720
2020	4,767
2021	3,814
2022	2,860
Thereafter	2,860
Total	31,632
Commercial servicing rights
Future amortization expense for amortizable intangible assets [Line Items]
Six months ending December 31, 2017	397
Year ending December 31,
2018	744
2019	596
2020	443
2021	378
2022	304
Thereafter	242
Total	$ 3,104