Income Taxes - Reconciliation of The Provision for Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Income tax expense computed at statutory rate	$ 42,136,000	$ 31,418,000	$ 11,098,000
State income taxes, net of federal tax benefit	5,064,000	4,015,000	998,000
Federal jobs credits	(4,550,000)	(3,900,000)	(2,925,000)
Tax exempt interest	(457,000)	(132,000)	(13,000)
Other, net	798,000	339,000	700,000
Tax provision	42,991,000	$ 31,740,000	$ 9,858,000
Unrecognized tax benefits	$ 0