Note 8 - Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2016

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Fair Value Measurements Using
June 30, 2016	Fair Value		Quoted Prices in Active Markets For Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents	$	37,543	$	37,543	$	–	$	–
Restricted cash and cash equivalents		16,700		16,700		–		–
Marketable equity securities		141,756		141,756		–		–
Corporate debt securities		75,118		38,282		36,836		–
Commercial mortgage–backed securities		56,903		–		56,903		–
U.S. Treasury securities		25,373		25,373		–		–
State and municipal securities		15,666		–		15,666		–
Total financial assets	$	369,059	$	259,654	$	109,405	$	–

	Fair Value Measurements Using
December 31, 2015	Fair Value		Quoted Prices in Active Markets For Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash and cash equivalents	$	38,208	$	38,208	$	–	$	–
Restricted cash and cash equivalents		11,106		11,106		–		–
Marketable equity securities		116,168		116,168		–		–
Corporate debt securities		71,143		32,683		38,460		–
Mortgage-backed securities		60,910		–		60,910		–
U.S. Treasury securities		21,033		21,033		–		–
State and municipal securities		16,780		–		16,780		–
Total financial assets	$	335,348	$	219,198	$	116,150	$	–