Parent Company Financial Statements (Statements of Condition) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investment in subsidiaries:
Other assets	$ 36,606	$ 30,844
Total assets	4,065,398	3,864,230
LIABILITIES AND SHAREHOLDERS' EQUITY
Accrued interest and other liabilities	49,996	44,479
Shareholders’ equity	403,413	391,547	$ 363,190	$ 245,109
Total liabilities and shareholders’ equity	4,065,398	3,864,230
Parent Company [Member]
ASSETS
Cash	29,365	29,905
Investment in subsidiaries:
Investment in subsidiary	444,235	429,100
Receivable from subsidiary	107	107
Other assets	14,806	12,420
Total assets	488,513	471,532
LIABILITIES AND SHAREHOLDERS' EQUITY
Subordinated debentures	58,911	58,755
Due to subsidiary	17	37
Accrued interest and other liabilities	26,172	21,193
Shareholders’ equity	403,413	391,547
Total liabilities and shareholders’ equity	$ 488,513	$ 471,532