Retirement Agreements and Other Postretirement Benefit Plan (Details) (USD $)	12 Months Ended
	Dec. 31, 2014 H	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Minimum number of years employed in order to participate in the 401(k) plan	1 year
Minimum number of hours worked annually in order to participate in the 401(k) plan	1,000
Defined contribution plan contribution percent	3.00%
Expenses related to the 401(k) plan	$ 676,000	$ 579,000	$ 518,000
Amount accrued for all deferred compensation plan agreements	7,111,000	6,580,000
Amount recognized in accumulated other comprehensive income, before tax	(118,150)	(73,246)	(155,234)
Amount recognized in accumulated other comprehensive income, net of tax	(77,988)	(48,353)	(102,454)
Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract]
2015	4,478
2016	4,885
2017	9,056
2018	13,962
2019	15,577
Thereafter	$ 147,312
Minimum
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Noncompete period following employment	2 years