v3.7.0.1

Long Term Debt - Additional Information (Detail) - USD ($) | 3 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2017 | Jun. 30, 2016 | Jun. 30, 2017 | Jun. 30, 2016 | Dec. 31, 2016 | Mar. 17, 2014
Debt Instrument [Line Items] |  |  |  |  |  |
Letters of credit outstanding under the facility | $ 12,400,000 |  | $ 12,400,000 |  | $ 13,000,000 |
5.25% Senior Notes due March 15, 2019 [Member] | Senior Notes [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Interest rate on Senior Notes | 5.25% |  | 5.25% |  |  | 5.25%
Maturity date of Senior notes payable |  |  | Mar. 15, 2019 |  |  |
Debt instrument interest rate term |  |  | Interest is payable semi-annually on March 15 and September 15 of each year. |  |  |
Debt instrument redemption date |  |  | On or after March 15, 2016 |  |  |
Percentage of principal amount redeemed |  |  | 101.00% |  |  |
Debt instrument restrictive covenants |  |  | The indenture governing the 2019 Notes (the “2019 Indenture”) contains, among other things, certain restrictive covenants, including limitations on incurring indebtedness, creating liens, selling assets and entering into certain transactions with affiliates. The covenants also limit PHI’s ability to, among other things, pay cash dividends on common stock, repurchase or redeem common or preferred equity, prepay subordinated debt and make certain investments. |  |  |
Interest Expense Fund [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Periodic payment of debt interest | $ 1,200,000 | $ 600,000 | $ 15,300,000 | $ 14,300,000 |  |
Revolving Credit Facility [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Revolving credit facility, maturity date |  |  | Oct. 01, 2018 |  |  |
Increased Borrowing capacity | $ 150,000,000 |  | $ 150,000,000 |  |  |
Revolving Credit facility, Covenants, consolidated working capital ratio | 200.00% |  | 200.00% |  |  |
Revolving Credit facility, Covenants, consolidated net worth ratio | 150.00% |  | 150.00% |  |  |
Revolving Credit facility, Covenants, fixed coverage ratio | 110.00% |  | 110.00% |  |  |
Revolving Credit facility, Covenants, consolidated net worth | $ 450,000,000 |  | $ 450,000,000 |  |  |
Letters of credit outstanding under the facility | $ 7,600,000 |  | $ 7,600,000 |  |  |
Revolving Credit Facility [Member] | LIBOR [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
LIBOR plus interest rate on borrowed funds |  |  | 2.25% |  |  |

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- Definition Description of covenants that limit or prohibit certain actions or activities without the lender's prior consent within a specified period of time or until certain specified targets are achieved for example, reduction of the debt or an increase in net worth to a specified amount). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(e)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823 + Details
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