Investments in Debt and Equity Securities and Other Investments - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Investment Holdings [Line Items]
Available for sale investments gross pre-tax unrealized gain (loss)	$ 5,358		$ 5,358		$ 5,181
Unrealized gain (loss) on investments, net of tax	(99)	$ 578	283	$ 909
Proceeds from sale of investments available for sale			385	1,277
Pre tax reclassification of net investment realized gain (loss) into net income			284	340
Reclassification of net investment realized gain (loss) into net income, net of tax	16		173	$ 207
HealthCare Partners (HCP)
Investment Holdings [Line Items]
Required minimum cash balance	54,200		54,200
Preferred Stock
Investment Holdings [Line Items]
Preferred stock, in a privately held company	$ 5,000		5,000
Certificates of deposit and money market funds
Investment Holdings [Line Items]
Unrealized gain (loss) on investments, pre tax			461
Unrealized gain (loss) on investments, net of tax			$ 283