Goodwill and Identifiable Intangible Assets - Schedule of Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 101,663	$ 101,663
Accumulated Amortization	80,983	74,117
Net Carrying Amount	$ 20,680	27,546
Remaining Weighted-Average Amortization Periods in Years	6 years 7 months 6 days
Core Deposit Intangibles [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 85,824	85,824
Accumulated Amortization	67,843	61,603
Net Carrying Amount	$ 17,981	24,221
Remaining Weighted-Average Amortization Periods in Years	5 years 7 months 6 days
Insurance Intangibles [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 13,824	13,824
Accumulated Amortization	11,615	11,117
Net Carrying Amount	$ 2,209	2,707
Remaining Weighted-Average Amortization Periods in Years	15 years 1 month 6 days
Banking Charters [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,325	1,325
Accumulated Amortization	877	811
Net Carrying Amount	$ 448	514
Remaining Weighted-Average Amortization Periods in Years	6 years 8 months 12 days
Borrower Relationship Intangible [Member]
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 690	690
Accumulated Amortization	648	586
Net Carrying Amount	$ 42	$ 104
Remaining Weighted-Average Amortization Periods in Years	7 months 6 days