Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Property and equipment, accumulated depreciation	[1]	$ 101,380	$ 92,933
Intangible assets, amortization		$ 4,178	$ 1,400
Preferred stock, par value		$ 0.01	$ 0.01
Preferred stock, shares authorized		1,000,000	1,000,000
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Common stock, par value		$ 0.01	$ 0.01
Common stock, shares authorized		300,000,000	300,000,000
Common stock, shares issued		87,264,910	85,953,253
Common stock, shares outstanding		70,062,364	70,151,357
Treasury stock, shares		17,202,546	15,801,896

[1] Property and equipment which were fully depreciated and no longer in use by the Company were retired during the years ended December 31, 2020 and 2019; therefore, both the cost of the asset and the related accumulated depreciation balances were reduced to zero for these assets.