Parent Company Only Financial Information (Condensed Statements of Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements
Net gain on securities transactions	$ 68	$ (1)	$ 767	$ 96	$ 56	$ 62	$ 11	$ 600	$ 930	$ 729	$ 398
Net loss on other transactions									(707)	(520)	67
Total interest income									115,444	108,333	80,200
Other expense	25,529	25,411	25,408	25,274	25,306	24,876	26,902	23,198
Applicable income tax benefit	3,336	3,656	3,479	3,654	425	1,370	2,231	(151)	14,125	3,875	7,494
Net income	$ 7,408	$ 7,792	$ 7,962	$ 7,995	$ 2,583	$ 4,134	$ 4,913	$ (689)	31,157	10,941	16,684
Bank
Condensed Financial Statements
Dividends from subsidiary bank									20,500	17,500	21,000
Non-Bank
Condensed Financial Statements
Dividends from subsidiary bank									1,250	2,000	500
Holding Company
Condensed Financial Statements
Interest and other income									209	206	205
Total interest income									21,959	19,706	21,705
Interest on junior subordinated debentures held by subsidiary trust									397	304	0
Intercompany management fees									1,131	3,171	1,546
Other expense									3,154	5,653	4,578
Total expenses									4,682	9,128	6,124
Income before federal income taxes and equity in (excess dividends from) undistributed earnings of subsidiaries									17,277	10,578	15,581
Applicable income tax benefit									(1,718)	(3,139)	(2,102)
Equity in (excess dividends from) undistributed earnings of subsidiaries									12,162	(2,776)	(999)
Net income									$ 31,157	$ 10,941	$ 16,684