Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Aug. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Allowance for loan losses	$ 44,233		$ 24,863
Acquisition-related fair value adjustments	65,596		29,280
Accrued stock-based compensation	18,353		3,240
Loss and tax credit carry forwards	55,921		6,850
Acquisition built in loss carry forwards	31,316		0
Depreciation	3,900		4,333
Nonaccrual interest	8,064		4,994
Accrued expense	18,400		13,296
Other	17,861		5,951
Total deferred tax assets	263,644		92,807
Deferred tax liabilities:
Loan servicing rights	18,021		3,893
Core deposit intangible assets	9,938		7,379
Goodwill	6,350		5,808
Other	7,829		4,742
Total deferred tax liabilities	42,138		21,822
Net deferred tax asset before valuation allowance	221,506		70,985
Valuation allowance	(2,502)		(795)
Net deferred tax asset	$ 219,004	$ 155,900	$ 70,190