CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Trade accounts receivable-billed, allowance	$ 3,735	$ 3,115
Property and equipment, accumulated depreciation	98,029	93,278
Intangibles, accumulated amortization	125,437	119,381
Client contract costs, accumulated amortization	31,526	43,051
Long-term debt, unamortized discounts	$ 10,053	$ 14,549
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares reserved for employee stock purchase plan and stock incentive plans	3,661,000	4,460,000
Common stock, shares outstanding	32,891,000	33,158,000
Common stock warrants, vested	0	439,000
Common stock warrants, issued	950,000	1,425,000
Treasury stock, shares	35,356,000	34,779,000
Software
Intangibles, accumulated amortization	$ 125,437	$ 119,381
Acquired client contracts
Intangibles, accumulated amortization	$ 93,767	$ 82,692