Condensed Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Condensed Consolidated Balance Sheet [Abstract]
Allowance for doubtful accounts, Accounts receivable	$ 259	$ 1,176
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	600,000,000	600,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	230,000,000	230,000,000
Common stock, shares issued	35,833,000	35,790,000
Treasury stock, shares at cost	7,019,000	5,206,000