Income Taxes - Significant Components of the Company's Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred income tax assets:
Allowance for credit losses	$ 20,256	$ 18,464
Deferred compensation	3,338	3,440
Accrued compensation	3,630	2,506
Net operating loss carryforwards	8,893	9,859
Alternative minimum tax credit carryover	978	978
Unrealized loss on securities, net	7,910	1,271
Unrealized loss on derivative instruments	5,496	4,912
Other	3,588	6,198
Total deferred income tax assets	54,089	47,628
Deferred income tax liabilities:
Difference in book and tax basis of intangibles	1,573	1,927
Other	6,239	4,213
Excess of book basis in assets acquired and tax liabilities assumed over book carrying value:
Intangibles	9,473	7,122
Other	3,580	3,592
Total deferred income tax liabilities	20,865	16,854
Net deferred income tax asset	$ 33,224	$ 30,774