Accounts Payable and Accrued Expenses:

12 Months Ended

Dec. 31, 2012

8. Accounts Payable and Accrued Expenses:

Accounts payable and accrued expenses consist of the following (in thousands):


	December 31,
	2012		2011
Accounts payable	$	13,812	$	12,264
Accrued salaries and bonuses		160,495		147,613
Accrued payroll taxes and benefits		36,176		29,443
Accrued professional liability risks		17,466		13,218
Accrued contingent consideration		16,109		12,089
Accrual for uncertain tax positions		—		3,242
Other accrued expenses		11,603		16,666

	$	255,661	$	234,535

The net increase in accrued salaries and bonuses of $12.9 million, from $147.6 million at December 31, 2011 to $160.5 million at December 31, 2012, is primarily due to performance-based incentive compensation accrued during the year ended December 31, 2012, partially offset by the payment of performance-based incentive compensation during the first quarter of 2012. A majority of the Company’s payments for performance-based incentive compensation is paid annually in the first quarter.