Income Taxes (Detail Textuals) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income tax expense	$ 15,389	$ 11,124	$ 28,967	$ 21,517
Income tax effective tax rate	37.90%	38.40%	37.90%	37.70%
Valuation allowance on deferred tax assets	$ 4,570		$ 4,570		$ 4,280
Valuation allowance related to specific state income tax credits			4,570
Net deferred tax asset realized based upon future taxable income	158,000		158,000
Unrecognized income tax benefits	$ 4,180		$ 4,180		$ 3,980