Income Taxes (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income tax expense (benefit) attributable to earnings (loss) from operations
Computed income tax expense	$ 73,760	$ 57,612	$ 48,768
State and local tax expense	4,207	6,709	5,544
Permanent differences, including domestic production activities deduction	(724)	523	(626)
Adjustments for uncertain tax positions	204	206	(166)
Other, net	(156)	24	(1,080)
Total income tax expense	$ 77,291	$ 65,074	$ 52,440