Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets
Allowance for loan and lease losses	$ 33,313	$ 32,890
Acquisition fair market value adjustments	6,380	4,139
Deferred compensation	6,251	5,640
Employee benefits	2,939	2,615
Net operating loss carryforwards	2,525	2,841
Available-for-sale debt securities	2,244	0
Interest rate swap agreements	955	2,379
Other real estate owned	801	5,126
Other	4,798	3,673
Total gross deferred tax assets	60,206	59,303
Deferred tax liabilities
Intangibles	(12,667)	(4,161)
Depreciation of premises and equipment	(10,776)	(2,863)
Deferred loan costs	(6,436)	(5,854)
FHLB stock dividends	(2,722)	(2,602)
Debt modification costs	(1,173)	(1,591)
Available-for-sale debt securities	0	(1,707)
Other	(2,868)	(2,181)
Total gross deferred tax liabilities	(36,642)	(20,959)
Net deferred tax asset	$ 23,564	$ 38,344