CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Property and equipment, Accumulated depreciation	$ 57,103	$ 60,284
Common stock, shares authorized (in shares)	180,000,000	180,000,000
Common stock, issued (in shares)	92,332,565	92,322,905
Common stock, outstanding (in shares)	75,329,557	92,302,636
Treasury stock, shares (in shares)	17,003,008	20,269