2.2.0.25falsefalse0214 - Disclosure - Derivativestruefalsefalse1falsefalseUSDfalsefalse1/1/2011 - 3/31/2011 USD ($) / shares USD ($) $Jan-01-2011_Mar-31-2011http://www.sec.gov/CIK0000780053duration2011-01-01T00:00:002011-03-31T00:00:00USDEPSDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0nhp_DerivativesAbstractnhpfalsenadurationDerivatives Abstract.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringDerivatives Abstract.falsefalseDerivatives [Abstract]3false0us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseverboselabel1falsefalsefalse00  <div style="font-family: 'Times New Roman',Times,serif; margin-left: 0in; "> <div align="justify" style="font-size: 10pt; margin-top: 10pt"><b>14. Derivatives</b> </div> <div align="justify" style="font-size: 10pt; margin-top: 10pt; text-indent: 8%">During August 2010, we entered into six 12-month forward-starting interest rate swap agreements for an aggregate notional amount of $250.0 million at a weighted average rate of 3.16%. We entered into these swap agreements in order to hedge the expected interest payments associated with fixed rate debt forecasted to be issued in 2011. The swap agreements each have an effective date of August 1, 2011 and a termination date of August 1, 2021. We expect to settle the swap agreements when the forecasted debt is issued. We assessed the effectiveness of these swap agreements as hedges at inception and on March 31, 2011 and consider these swap agreements to be highly effective cash flow hedges. The swap agreements are recorded under the caption “Other assets” on our consolidated balance sheets at their aggregate estimated fair value of $12.2 million and $11.2 million at March 31, 2011 and December 31, 2010, respectively. </div> <div align="justify" style="font-size: 10pt; margin-top: 10pt; text-indent: 8%">During 2006 and 2007, we entered into and settled Treasury lock agreements to hedge the expected interest payments associated with a portion of our senior notes. The settlement amounts were recorded as other comprehensive income and are being amortized over the life of the debt as a yield reduction. We expect to record $0.4 million of amortization during the next 12 months. </div> <div align="justify" style="font-size: 10pt; margin-top: 10pt; text-indent: 8%">The following table sets forth amounts included on our consolidated income statements related to the amortization of the Treasury lock agreements for the periods presented: </div> <div align="center"> <table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">  <tr valign="bottom"> <td width="72%"> </td> <td width="3%"> </td> <td width="1%"> </td> <td width="9%"> </td> <td width="1%"> </td> <td width="3%"> </td> <td width="1%"> </td> <td width="9%"> </td> <td width="1%"> </td> </tr> <tr style="font-size: 10pt" valign="bottom"> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="6"><b>Three months ended</b></td> <td> </td> </tr> <tr style="font-size: 10pt" valign="bottom"> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="6" style="border-bottom: 1px solid #000000"><b>March 31,</b></td> <td> </td> </tr> <tr style="font-size: 10pt" valign="bottom"> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>2011</b></td> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>2010</b></td> <td> </td> </tr> <tr style="font-size: 10pt" valign="bottom"> <td> </td> <td> </td> <td nowrap="nowrap" align="center" colspan="6"><b>(In thousands)</b></td> <td> </td> </tr>   <tr valign="bottom" style="background: #cceeff"> <td> <div style="margin-left:15px; text-indent:-15px">Amortization: </div></td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> <td> </td> </tr> <tr valign="bottom"> <td> <div style="margin-left:30px; text-indent:-15px">2007 Treasury lock agreements </div></td> <td> </td> <td align="left">$</td> <td align="right">68</td> <td> </td> <td> </td> <td align="left">$</td> <td align="right">64</td> <td> </td> </tr> <tr valign="bottom" style="background: #cceeff"> <td> <div style="margin-left:30px; text-indent:-15px">2006 Treasury lock agreements </div></td> <td> </td> <td> </td> <td align="right">67</td> <td> </td> <td> </td> <td> </td> <td align="right">62</td> <td> </td> </tr> <tr style="font-size: 1px"> <td> <div style="margin-left:30px; text-indent:-15px">  </div></td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td> <td> </td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td> <td> </td> </tr> <tr valign="bottom"> <td> <div style="margin-left:15px; text-indent:-15px">  </div></td> <td> </td> <td align="left">$</td> <td align="right">135</td> <td> </td> <td> </td> <td align="left">$</td> <td align="right">126</td> <td> </td> </tr> <tr style="font-size: 1px"> <td> <div style="margin-left:15px; text-indent:-15px">  </div></td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td> <td> </td> <td> </td> <td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td> <td> </td> </tr>  </table> </div> <div align="justify" style="font-size: 10pt; margin-top: 10pt; text-indent: 8%">During 2008, the unconsolidated joint venture we have with a state pension fund investor entered into an interest rate swap contract. The fair value of this contract at March 31, 2011 and December 31, 2010 was $11.4 million and $12.8 million, respectively, which is included as a liability on the joint venture’s balance sheets. As of March 31, 2011, we had recorded our pro rata share of the unconsolidated joint venture’s accumulated other comprehensive loss related to this contract of $2.8 million. </div>   </div>  <div style="font-family: 'Times New Roman',Times,serif; margin-left: 0in; "> <div align="center" style="font-size: 10pt; margin-top: 0pt"> <b> </b> </div> <div align="center" style="font-size: 10pt; margin-top: 0pt"> <b> </b> </div> </div>  <!-- Begin Block Tagged NotefalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringThis element can be used to disclose the entity's entire derivative instruments and hedging activities disclosure as a single block of text. 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