Cash, Cash Equivalents and Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2018

Cash, Cash Equivalents and Marketable Securities [Abstract]

Summary of investments in cash, cash equivalents and marketable securities

The following table summarizes our cash and investments in cash equivalents and marketable securities held by investment managers and overnight investments:

	June 30, 2018			December 31, 2017
	(in thousands)
Overnight holdings
Money market funds (cash equivalents)	$	282,337		$	338,112
Investment holdings
Money market funds (cash equivalents)	17,354			22,634
Marketable securities	7,207			1,960
	306,898			362,706
Cash held in demand accounts	25,053			26,700
Outstanding checks	(16,033		)	(33,186		)
Total cash, cash equivalents and marketable securities	$	315,918		$	356,220
Cash and cash equivalents	$	308,711		$	354,260
Marketable securities	7,207			1,960
Total cash, cash equivalents and marketable securities	$	315,918		$	356,220