Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2016

Fair Value Disclosures [Abstract]

Summary of Placement in the Fair Value Hierarchy of Financial Assets that are Measured at Fair Value on a Recurring Basis

The following table presents the placement in the fair value hierarchy of financial assets that are measured at fair value on a recurring basis, including the items for which the fair value option has been elected, at March 31, 2016:

	Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		March 31, 2016
Assets
U.S. government debt securities	$	—	$	189,971	$	—	$	189,971
Equity securities	50,189		11,133		—		61,322
Other	—		399		—		399
Total	$	50,189	$	201,503	$	—	$	251,692

The following table presents the placement in the fair value hierarchy of financial assets that are measured at fair value on a recurring basis, including the items for which the fair value option has been elected, at December 31, 2015:

	Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		December 31, 2015
Assets
U.S. government debt securities	$	—	$	207,704	$	—	$	207,704
Equity securities	65,850		17,803		—		83,653
Other	—		405		—		405
Total	$	65,850	$	225,912	$	—	$	291,762