Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, net		$ 46,931	$ 43,909
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2017		5,373
2018		4,640
2019		4,272
2020		4,117
2021		3,738
Thereafter		24,791
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance		385,689	378,008
Goodwill, Accumulated Impairment Beginning Balance		(228)	(228)
Goodwill, Net Beginning Balance		385,461	377,780
Goodwill acquired during period		69,496	7,681
Adjustment	[1]	(6,058)
Goodwill, Gross Ending Balance		449,127	385,689
Goodwill, Accumulated Impairment Ending Balance		(228)	(228)
Goodwill, Net Ending Balance		448,899	385,461
Commercial [Member]
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance		277,044	269,363
Goodwill, Accumulated Impairment Beginning Balance		0	0
Goodwill, Net Beginning Balance		277,044	269,363
Goodwill acquired during period		1,210	7,681
Adjustment	[1]	(6,058)
Goodwill, Gross Ending Balance		272,196	277,044
Goodwill, Accumulated Impairment Ending Balance		0	0
Goodwill, Net Ending Balance		272,196	277,044
Consumer [Member]
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance		39,251	39,251
Goodwill, Accumulated Impairment Beginning Balance		(228)	(228)
Goodwill, Net Beginning Balance		39,023	39,023
Goodwill acquired during period		0	0
Adjustment	[1]	0
Goodwill, Gross Ending Balance		39,251	39,251
Goodwill, Accumulated Impairment Ending Balance		(228)	(228)
Goodwill, Net Ending Balance		39,023	39,023
Wealth Management [Member]
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance		69,394	69,394
Goodwill, Accumulated Impairment Beginning Balance		0	0
Goodwill, Net Beginning Balance		69,394	69,394
Goodwill acquired during period		2,126	0
Adjustment	[1]	0
Goodwill, Gross Ending Balance		71,520	69,394
Goodwill, Accumulated Impairment Ending Balance		0	0
Goodwill, Net Ending Balance		71,520	69,394
Funds Management and Other [Member]
Goodwill [Roll Forward]
Goodwill, Gross Beginning Balance		0	0
Goodwill, Accumulated Impairment Beginning Balance		0	0
Goodwill, Net Beginning Balance		0	0
Goodwill acquired during period		66,160	0
Adjustment	[1]	0
Goodwill, Gross Ending Balance		66,160	0
Goodwill, Accumulated Impairment Ending Balance		0	0
Goodwill, Net Ending Balance		66,160	0
Core deposits premiums [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross		35,879	29,369
Accumulated amortization		29,369	29,101
Finite-lived intangible assets, net		6,510	268
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2017		808
2018		732
2019		716
2020		697
2021		675
Thereafter		2,882
Other identifiable intangible assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, gross		60,951	55,509
Accumulated amortization		20,530	11,868
Finite-lived intangible assets, net		40,421	$ 43,641
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2017		4,565
2018		3,908
2019		3,556
2020		3,420
2021		3,063
Thereafter		$ 21,909

[1] Completion of an external audit of Heartland Food Products resulted in a reallocation of the purchase price between net assets acquired, intangible assets and goodwill during 2016.