Securities Available for Sale - Amortized cost/fair value (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 339,691
Gross Unrealized Gains	17
Gross Unrealized Losses	(1,189)
Securities available for sale:	338,519	$ 0
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	251,253
Gross Unrealized Gains	4
Gross Unrealized Losses	(1,144)
Securities available for sale:	250,113
Asset-backed securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	54,990
Gross Unrealized Gains	4
Gross Unrealized Losses	(35)
Securities available for sale:	54,959
U.S. agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	20,602
Gross Unrealized Gains	5
Gross Unrealized Losses	(4)
Securities available for sale:	20,603
Municipal securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,840
Gross Unrealized Gains	3
Gross Unrealized Losses	0
Securities available for sale:	5,843
Other securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,006
Gross Unrealized Gains	1
Gross Unrealized Losses	(6)
Securities available for sale:	$ 7,001

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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