Available-for-Sale Securities (Tables)

3 Months Ended

Mar. 31, 2013

Schedule of Available-for-sale Securities [Line Items]

Schedule of Available-for-sale Securities Reconciliation [Table Text Block]

Available-for-Sale Securities by Major Security Types (in thousands)

	March 31, 2013
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)		Fair Value
Certificates of deposit	$	500,000	$	44	$	—	$	500,044
Total	$	500,000	$	44	$	—	$	500,044

Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]

Schedule of Available-for-sale Securities [Line Items]

Investments Classified by Contractual Maturity Date [Table Text Block]

Available-for-Sale Securities by Contractual Maturity (in thousands)

	March 31, 2013
Year of Maturity	Amortized Cost		Fair Value
Due in one year or less	$	500,000	$	500,044

Schedule of Interest Rate Payment Terms For Investments [Table Text Block]

Interest Rate Payment Terms of Available-for-Sale Securities (in thousands)

	March 31, 2013
Amortized cost of available-for-sale securities:
Fixed-rate	$	500,000