Federal Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets, Gross [Abstract]
Allowance for loan losses	$ 24,863	$ 26,489
Acquisition-related fair value adjustments	29,280	19,457
Accrued expenses not currently deductible	9,331	7,819
Net operating loss carryover	7,130	0
Premises and equipment	4,333	3,311
Nonaccrual loan interest	4,994	4,682
Other	15,296	9,418
Total deferred tax assets	95,227	71,176
Deferred Tax Liabilities, Gross [Abstract]
Core deposit intangible assets	7,379	5,072
Goodwill	5,808	5,205
Mortgage servicing rights	3,893	4,276
Other	7,957	3,884
Total deferred tax liabilities	25,037	18,437
Net deferred tax assets	$ 70,190	$ 52,739