Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Measurements [Abstract]

Assets and Liabilities Measured at Fair Value on a Recurring Basis

	As of March 31, 2018								As of December 31, 2017
	Fair Value Hierarchy								Fair Value Hierarchy
(in thousands)	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Cash and cash equivalents(a)	$	174,340	$	—	$	—	$	174,340	$	192,868	$	—	$	—	$	192,868
Restricted cash(a)		4,090		—		—		4,090		4,780		—		—		4,780
Investments in lieu of retainage(b)		65,708		2,101		—		67,809		69,891		2,405		—		72,296
Total	$	244,138	$	2,101	$	—	$	246,239	$	267,539	$	2,405	$	—	$	269,944

(a) Includes money market funds with original maturity dates of three months or less.

(b) Investments in lieu of retainage are included in retainage receivable and are comprised of money market funds and municipal bonds, the majority of which are rated A3 or better. The fair values of the money market funds are measured using quoted market prices; therefore, they are classified as Level 1 assets. The fair values of municipal bonds are measured using readily available pricing sources for comparable instruments; therefore, they are classified as Level 2 assets. All of the above investments are available-for-sale securities.