Parent Company Only Financial Information (Condensed Statements of Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements
Net gain on investment securities	$ 94	$ 97	$ (57)	$ 30	$ 0	$ 0	$ (147)	$ 1	$ 164	$ (146)	$ 2,983
Total interest income									170,095	151,264	126,525
Other expense	32,568	31,841	31,282	30,913	29,713	29,292	29,054	27,318
Applicable income tax expense	2,767	3,281	2,238	3,377	2,470	2,821	1,012	2,383	11,663	8,686	18,732
Net income	$ 14,860	$ 14,868	$ 9,598	$ 14,369	$ 13,897	$ 12,725	$ 7,892	$ 11,741	53,695	46,255	38,471
Bank
Condensed Financial Statements
Dividends from subsidiary bank									37,000	13,500	27,000
Non-Bank
Condensed Financial Statements
Dividends from subsidiary bank									0	2,500	20,000
Holding Company
Condensed Financial Statements
Net gain on investment securities									0	0	2,602
Interest and other income									81	357	237
Total interest income									37,081	16,357	49,839
Interest on junior subordinated debentures held by subsidiary trust									534	520	346
Payment for Administrative Fees									1,607	1,561	1,361
Other expense									5,432	4,647	3,380
Total expense									7,573	6,728	5,087
Income before federal income taxes and equity in undistributed earnings of subsidiaries									29,508	9,629	44,752
Applicable income tax expense									(1,670)	(2,511)	(1,309)
Equity in (excess dividends from) undistributed earnings of subsidiaries									22,517	34,115	(7,590)
Net income									$ 53,695	$ 46,255	$ 38,471