Fair Value of Financial Instruments (Tables)

9 Months Ended

Sep. 30, 2019

Schedule of assets and liabilities measured at fair vale on a recurring basis

All assets measured at fair value are categorized in the table below based upon the lowest level of significant input to the valuations. All fair value measurements at the reporting date were on a recurring basis.



September 30, 2019 (In thousands)	Quoted Prices in Active Markets for Identical Instruments (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Recurring fair value measurements
Financial Assets:
U.S. Treasury securities	$	271,359	$	—	$	—	$	271,359
U.S. agency securities	—		33,544		—		33,544
U.S. agency mortgage-backed securities	—		829,748		—		829,748
Municipal debt securities	—		364,140		—		364,140
Non-U.S. government securities	—		49,935		—		49,935
Corporate debt securities	—		824,632		—		824,632
Residential and commercial mortgage securities	—		283,790		—		283,790
Asset-backed securities	—		324,861		—		324,861
Money market funds	252,604		—		—		252,604
Total assets at fair value (1)	$	523,963	$	2,710,650	$	—	$	3,234,613


(1)	Does not include the fair value of embedded derivatives, which we have accounted for separately as freestanding derivatives and included in other assets in our condensed consolidated balance sheet. See Note 4 for more information.



December 31, 2018 (In thousands)	Quoted Prices in Active Markets for Identical Instruments (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Recurring fair value measurements
Financial Assets:
U.S. Treasury securities	$	289,892	$	—	$	—	$	289,892
U.S. agency securities	—		32,997		—		32,997
U.S. agency mortgage-backed securities	—		637,178		—		637,178
Municipal debt securities	—		483,879		—		483,879
Non-U.S. government securities	—		45,001		—		45,001
Corporate debt securities	—		725,201		—		725,201
Residential and commercial mortgage securities	—		121,838		—		121,838
Asset-backed securities	—		284,997		—		284,997
Money market funds	139,083		—		—		139,083
Total assets at fair value	$	428,975	$	2,331,091	$	—	$	2,760,066