Fair Value of Financial Instruments (Reconciliation of Instrument with Unobservable Inputs) (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2014
Fair Value, Assets (Liabilities), Net Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance as of December 31, 2013	$ 43,847
Unrealized gain included in other comprehensive income, net	8,598
Changes in fair value included in net income, net	4,004
Purchases/issuances	147,591
Amortization included in net income, net	(3,065)
Ending balance as of June 30, 2014	200,975
Fair Value, Inputs, Level 3 [Member] \| Commercial Mortgage Backed Securities [Member]
Fair Value, Assets (Liabilities), Net Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance as of December 31, 2013	60,583
Unrealized gain included in other comprehensive income, net	8,598
Changes in fair value included in net income, net	0
Purchases/issuances	151,197
Amortization included in net income, net	(3,065)
Ending balance as of June 30, 2014	217,313
Fair Value, Inputs, Level 3 [Member] \| Series D Preferred Stock Embedded Derivative [Member]
Fair Value, Assets (Liabilities), Net Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance as of December 31, 2013	(16,736)
Unrealized gain included in other comprehensive income, net	0
Changes in fair value included in net income, net	5,216
Amortization included in net income, net	0
Ending balance as of June 30, 2014	(11,520)
Fair Value, Inputs, Level 3 [Member] \| Contingent Consideration [Member]
Fair Value, Assets (Liabilities), Net Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Unrealized gain included in other comprehensive income, net	0
Changes in fair value included in net income, net	(1,212)
Purchases/issuances	(3,606)
Amortization included in net income, net	0
Ending balance as of June 30, 2014	$ (4,818)

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Amortization Included in Earnings

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- Definition

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Net, Amortization Included in Earnings

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No definition available.

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Net, Gain (Loss) Included in Earnings

+ References

No definition available.

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Net, Gain (Loss) Included in Other Comprehensive Income (Loss)

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No definition available.

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Net, Purchases, (Sales), Issuances, (Settlements)

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No definition available.

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset (Liability), Net Value

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Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Amortization Included in Earnings

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No definition available.

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- Definition

Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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- Definition

Amount of gain (loss) recognized in other comprehensive income (loss) for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1a)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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- Definition

Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph c

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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- Definition

Amount of gain (loss) recognized in other comprehensive income (loss) for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1a)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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Amount of purchases, (sales), issuances and (settlements) of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph c

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

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