Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Allowance for loan losses	$ 45,763	$ 24,863
Acquisition-related fair value adjustments	62,078	29,280
Accrued stock-based compensation	18,891	3,240
Loss and tax credit carry forwards	47,977	7,235
Acquisition built in loss carry forward	28,469	0
Depreciation	3,896	4,333
Nonaccrual loan interest	9,465	4,994
Accrued expense	20,858	13,296
Other	7,401	5,951
Total deferred tax assets	244,798	93,192
Deferred tax liabilities:
Loan servicing rights	20,450	3,893
Core deposit intangible assets	11,844	7,379
Goodwill	6,373	5,808
Other	(715)	4,742
Total deferred tax liabilities	37,952	21,822
Net deferred tax asset before valuation allowance	206,846	71,370
Valuation allowance	(2,239)	(1,180)
Net deferred tax asset	$ 204,607	$ 70,190