Share Based Compensation, 401(k) Plan and Deferred Compensation - Restricted Performance Share Units (Details) - Restricted Performance Share Units Plan [Member] - Executive Officer [Member] - USD ($) $ in Thousands				3 Months Ended
	Mar. 01, 2017	Feb. 22, 2016	Feb. 23, 2015	Mar. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2017, Shares				378,977
Granted, shares				174,854
Units Cancelled				0
Non-vested at March 31, 2017, Shares				553,831
Units Granted	174,854	231,388	186,395
Fair Value of Units on Grant Date (in thousands)	$ 3,735	$ 3,558	$ 3,933
February 23, 2015 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2017, Shares				147,589
Granted, shares				0
Units Cancelled				0
Non-vested at March 31, 2017, Shares				147,589
Measurement Period Commencement Date				Jan. 01, 2015
Measurement Period End Date				Dec. 31, 2017
February 22, 2016 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2017, Shares				231,388
Granted, shares				0
Units Cancelled				0
Non-vested at March 31, 2017, Shares				231,388
Measurement Period Commencement Date				Jan. 01, 2016
Measurement Period End Date				Dec. 31, 2018
March 01, 2017 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2017, Shares				0
Granted, shares				174,854
Units Cancelled				0
Non-vested at March 31, 2017, Shares				174,854
Measurement Period Commencement Date				Jan. 01, 2017
Measurement Period End Date				Dec. 31, 2019