Income Taxes (Details) - Components of Effective Tax Rate - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Statutory federal income tax rate	$ 48,482	$ 41,934	$ 35,167
Statutory federal income tax rate (percent of pretax income)	35.00%	35.00%	35.00%
Tax-exempt income, net of interest expense disallowance	$ (5,439)	$ (6,752)	$ (7,520)
Tax-exempt income, net of interest expense disallowance (percent of pretax income)	(3.90%)	(5.60%)	(7.50%)
State income tax, net of federal income tax effect	$ 4,323	$ 4,665	$ 4,503
State income tax, net of federal income tax effect (percent of pretax income)	3.10%	3.90%	4.50%
Other	$ (1,195)	$ (2,100)	$ (980)
Other (percent of pretax income)	(0.90%)	(1.80%)	(1.00%)
Total income tax expense	$ 46,171	$ 37,747	$ 31,170
Effective tax rate	33.30%	31.50%	31.00%