Fair Value Measurements (Assets Measured at Fair Value on a Recurring Basis) (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets (mutual funds)	$ 1,354	$ 1,477
Level 1 [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets (mutual funds)	1,354	1,477
Level 2 [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets (mutual funds)	0	0
Level 3 [Member]
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Deferred compensation plan assets (mutual funds)	$ 0	$ 0