Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for loan losses	$ 24,019	$ 20,446
Acquisition-related fair value adjustments	16,511	27,607
Unrealized loss on securities	10,040	2,751
Accrued stock-based compensation	3,239	4,082
Loss and tax credit carry forwards	30,169	57,969
Nonaccrual loan interest	10,830	6,155
Accrued expense	7,397	9,200
Other	4,888	9,330
Total deferred tax assets	107,093	137,540
Deferred tax liabilities:
Loan servicing rights	14,941	13,446
Core deposit intangible assets	4,966	6,022
Goodwill	4,281	4,076
Deferred loan fees	4,963	4,551
Prepaid expenses	5,625	7,390
Other	5,894	3,184
Total deferred tax liabilities	40,670	38,669
Net deferred tax asset before valuation allowance	66,423	98,871
Valuation allowance	(1,467)	(1,150)
Net deferred tax asset	$ 64,956	$ 97,721