Income Taxes - Reconciliation Of Actual To Expected Tax Expense (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
Income Tax Disclosure [Abstract]
Computed “expected” income tax expense									$ 7,365	$ 8,552	$ 8,646
State income taxes, net									384	794	886
Non-deductible merger expenses									0	0	130
Tax-exempt interest on investment securities									(566)	(507)	(415)
Tax-exempt gain on purchase of mortgage affiliate									0	0	(1,050)
Amortization of investment in low income housing tax credit partnerships									2,868	2,684	1,337
Low income housing credits									(3,540)	(2,446)	(1,298)
Other									(459)	(293)	(63)
Total	$ 1,458	$ 1,027	$ 1,868	$ 1,699	$ 1,673	$ 2,678	$ 2,686	$ 1,747	$ 6,052	$ 8,784	$ 8,173