Investments (Tables)

9 Months Ended

Sep. 30, 2014

Investments, Debt and Equity Securities [Abstract]

Schedule of Investments

At September 30, 2014 investments classified as available-for-sale securities were as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Debt securities:
U.S. Treasury securities	$	484,771	$	135	$	—	$	484,906
Corporate debt securities	101,210		—		3,826		97,384
Preferred stock	13,513		211		—		13,724
	$	599,494	$	346	$	3,826	$	596,014

At December 31, 2013 investments classified as available-for-sale securities were as follows:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Debt securities:
U.S. Treasury securities	$	124,861	$	88	$	—	$	124,949
Corporate debt securities	24,236		—		2,213		22,023
	$	149,097	$	88	$	2,213	$	146,972

Contractual Maturities of Investments

The net carrying value and estimated fair value of investments classified as available-for-sale at September 30, 2014, by contractual maturity are shown in the following table. Actual maturities may differ from contractual maturities because certain borrowers have the right to call or prepay obligations.

	Amortized Cost		Fair Value
Due in one year or less	$	484,771	$	484,906
Due after one year through five years	101,210		97,384
	585,981		582,290
Preferred stock	13,513		13,724
	$	599,494	$	596,014