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Bank Note Payable and Term Note Payable (Details) - USD ($) |  |  | 12 Months Ended |  |
--- | --- | --- | --- | --- | ---
Aug. 26, 2013 | Sep. 27, 2012 | Dec. 31, 2015 | Dec. 31, 2013 | Dec. 31, 2014 | Oct. 29, 2014
Debt Instrument [Line Items] |  |  |  |  |  |
Amount drawn down |  |  |  | $ 220,000,000 |  |
Borrowings outstanding |  |  | $ 290,000,000 |  | $ 268,000,000 |
BAML Credit Facility | Federal Funds Rate |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.50% |  |  |
BAML Credit Facility | One month LIBOR |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.00% |  |  |
BAML Revolver |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Total available |  |  | $ 500,000,000 |  |  |
Additional borrowing capacity allowed by exercising an accordion feature |  |  | 250,000,000 |  |  |
Borrowings outstanding |  |  | $ 290,000,000 |  | $ 268,000,000 |
Extension available on debt |  |  | 12 months |  |  |
Facility fee (as a percent) |  |  | 0.25% |  |  |
Interest rate during period (as a percent) |  |  | 1.44% |  |  |
Weighted average interest rate (as a percent) |  |  | 1.54% |  | 1.41% |
BAML Revolver | A- | A3 | Minimum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Facility fee (as a percent) |  |  | 0.125% |  |  |
BAML Revolver | BBB+ | Baa1 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Facility fee (as a percent) |  |  | 0.15% |  |  |
BAML Revolver | BBB | Baa2 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Facility fee (as a percent) |  |  | 0.20% |  |  |
BAML Revolver | BBB- | Baa3 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Facility fee (as a percent) |  |  | 0.25% |  |  |
BAML Revolver | BBB- | Baa3 | Maximum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Facility fee (as a percent) |  |  | 0.30% |  |  |
BAML Revolver | LIBOR |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.25% |  |  |
BAML Revolver | LIBOR | A- | A3 | Minimum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.875% |  |  |
BAML Revolver | LIBOR | BBB+ | Baa1 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.925% |  |  |
BAML Revolver | LIBOR | BBB | Baa2 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.05% |  |  |
BAML Revolver | LIBOR | BBB- | Baa3 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.25% |  |  |
BAML Revolver | LIBOR | BBB- | Baa3 | Maximum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.65% |  |  |
BAML Revolver | Base Rate |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.25% |  |  |
BAML Revolver | Base Rate | A- | A3 | Minimum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.00% |  |  |
BAML Revolver | Base Rate | BBB+ | Baa1 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.00% |  |  |
BAML Revolver | Base Rate | BBB | Baa2 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.05% |  |  |
BAML Revolver | Base Rate | BBB- | Baa3 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.25% |  |  |
BAML Revolver | Base Rate | BBB- | Baa3 | Maximum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.65% |  |  |
BAML Term Loan |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Principal amount of loan |  |  | $ 400,000,000 |  |  |
Amount drawn down |  | $ 400,000,000 |  |  |  |
Weighted average interest rate (as a percent) |  |  | 2.20% |  |  |
BAML Term Loan | LIBOR |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.45% |  |  |
Fixed rate (as a percent) |  |  | 0.75% |  |  |
Term pursuant to interest rate swap agreement |  | 5 years |  |  |  |
BAML Term Loan | LIBOR | A- | A3 | Minimum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.95% |  |  |
BAML Term Loan | LIBOR | BBB+ | Baa1 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.025% |  |  |
BAML Term Loan | LIBOR | BBB | Baa2 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.20% |  |  |
BAML Term Loan | LIBOR | BBB- | Baa3 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.45% |  |  |
BAML Term Loan | LIBOR | BBB- | Baa3 | Maximum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.90% |  |  |
BAML Term Loan | Base Rate |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.45% |  |  |
BAML Term Loan | Base Rate | A- | A3 | Minimum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.00% |  |  |
BAML Term Loan | Base Rate | BBB+ | Baa1 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.025% |  |  |
BAML Term Loan | Base Rate | BBB | Baa2 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.20% |  |  |
BAML Term Loan | Base Rate | BBB- | Baa3 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.45% |  |  |
BAML Term Loan | Base Rate | BBB- | Baa3 | Maximum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.90% |  |  |
BMO Term Loan |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Principal amount of loan | $ 220,000,000 |  |  |  |  |
Amount drawn down | $ 220,000,000 |  |  |  |  |
Term of the borrowing | 7 years |  |  |  |  |
Additional loans allowed by exercising an accordion feature |  |  |  |  |  | $ 50,000,000
Effective interest rate (as a percent) |  |  | 3.97% |  |  |
BMO Term Loan | LIBOR |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.65% |  |  |
Fixed rate (as a percent) |  |  | 2.32% |  |  |
Term pursuant to interest rate swap agreement | 7 years |  |  |  |  |
BMO Term Loan | LIBOR | A- | A3 | Minimum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.05% |  |  |
BMO Term Loan | LIBOR | BBB+ | Baa1 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.15% |  |  |
BMO Term Loan | LIBOR | BBB | Baa2 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.35% |  |  |
BMO Term Loan | LIBOR | BBB- | Baa3 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.65% |  |  |
BMO Term Loan | LIBOR | BBB- | Baa3 | Maximum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 2.15% |  |  |
BMO Term Loan | Base Rate |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.65% |  |  |
BMO Term Loan | Base Rate | A- | A3 | Minimum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.05% |  |  |
BMO Term Loan | Base Rate | BBB+ | Baa1 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.15% |  |  |
BMO Term Loan | Base Rate | BBB | Baa2 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.35% |  |  |
BMO Term Loan | Base Rate | BBB- | Baa3 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.65% |  |  |
BMO Term Loan | Base Rate | BBB- | Baa3 | Maximum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.15% |  |  |
BMO Term Loan | Federal Funds Rate |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 0.50% |  |  |
BMO Term Loan | One month LIBOR |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Basis spread on variable rate (as a percent) |  |  | 1.00% |  |  |

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