Parent Company Financial Statements (Statement of Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Expenses:
Interest on junior subordinated debentures	$ 871	$ 964	$ 1,484
Legal and professional fees	2,741	2,336	2,330
Acquisition related expenses	989	0	0
Income before income taxes	64,343	59,823	52,680
Income tax benefit	(20,878)	(18,999)	(16,527)
Net income	43,465	40,824	36,153
Parent Company [Member]
Income:
Dividends from subsidiaries	23,399	20,116	24,481
Other income	13	13	20
Total income	23,412	20,129	24,501
Expenses:
Interest on junior subordinated debentures	871	964	1,484
Legal and professional fees	134	96	145
Acquisition related expenses	308	0	0
Other	295	253	279
Total expenses	1,608	1,313	1,908
Income before income taxes	21,804	18,816	22,593
Income tax benefit	557	454	661
Income before equity in undistributed earnings of subsidiaries	22,361	19,270	23,254
Equity in undistributed earnings of subsidiaries	21,104	21,554	12,899
Net income	$ 43,465	$ 40,824	$ 36,153