Debt - Additional Information (Detail) - USD ($) | Mar. 02, 2018 | Nov. 02, 2017 | Nov. 02, 2017 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Mar. 17, 2014 | Aug. 28, 2012 |
Debt Instrument [Line Items] | | | | | | | | |
Financing costs | | | | $ 19,420,000 | $ 14,350,000 | | | |
Outstanding senior notes | | | | 500,000,000 | | | | |
Loss on early extinguishment of debt | | | | (2,623,000) | (1,156,000) | $ (4,382,000) | | |
5 1/2% Senior Notes Due 2021 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Original principal amount | | | | | | | $ 200,000,000 | |
Outstanding senior notes | | | | $ 200,000,000 | | | | |
Senior notes expiration date | | | | 2021-04 | | | | |
Redemption percentage of senior notes, description | | | | As a percentage of par value, the 5 1⁄2% Notes are currently redeemable at 102.750%, 101.375% commencing April 15, 2018 and at par value commencing April 15, 2019. | | | | |
6 3/8% Senior Notes Due 2023 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Original principal amount | | | | | | | | $ 300,000,000 |
Outstanding senior notes | | | | $ 300,000,000 | | | | |
Senior notes expiration date | | | | 2023-04 | | | | |
Redemption percentage of senior notes, description | | | | As a percentage of par value, the 6 3/8 % Notes are redeemable at 103.188% commencing April 1, 2018, 102.125% commencing April 1, 2019, 101.063% commencing April 1, 2020 and at par value commencing April 1, 2021. | | | | |
6 3/8% Senior Notes Due 2023 [Member] | Subsequent Event [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Debt, called for redemption | $ 300,000,000 | | | | | | | |
Debt, redemption date | Apr. 2, 2018 | | | | | | | |
Interest Rate Swap [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Expiration date of revolving credit commitments | | | | Dec. 31, 2018 | | | | |
Interest rate on borrowings | | | | 1.50% | | | | |
Weighted average interest rate on outstanding borrowings | | | | 3.40% | | | | |
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Revolving credit commitment outstanding | | | | $ 600,000,000 | | | | |
Maximum [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Required debt to operating cash flow | | | | 8.50% | | | | |
Minimum [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Required debt to operating cash flow | | | | 1.00% | | | | |
Loans Payable [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Revolving credit commitment outstanding | | | | $ 32,100,000 | | | | |
Debt Instrument, Redemption, Period One [Member] | 5 1/2% Senior Notes Due 2021 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Redemption percentage of senior notes | | | | 102.75% | | | | |
Redemption of senior notes commencing date | | | | Apr. 15, 2018 | | | | |
Debt Instrument, Redemption, Period Two [Member] | 5 1/2% Senior Notes Due 2021 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Redemption percentage of senior notes | | | | 101.375% | | | | |
Redemption of senior notes commencing date | | | | Apr. 15, 2018 | | | | |
Debt Instrument, Redemption, Period Three [Member] | 6 3/8% Senior Notes Due 2023 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Redemption percentage of senior notes | | | | 103.188% | | | | |
Redemption of senior notes commencing date | | | | Apr. 1, 2018 | | | | |
Debt Instrument, Redemption, Period Four [Member] | 6 3/8% Senior Notes Due 2023 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Redemption percentage of senior notes | | | | 102.125% | | | | |
Redemption of senior notes commencing date | | | | Apr. 1, 2019 | | | | |
Debt Instrument, Redemption, Period Five [Member] | 6 3/8% Senior Notes Due 2023 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Redemption percentage of senior notes | | | | 101.063% | | | | |
Redemption of senior notes commencing date | | | | Apr. 1, 2020 | | | | |
Bank Credit Facility [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Unused revolving credit commitments | | | | $ 333,200,000 | | | | |
Letter of Credit [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Revolving credit commitment outstanding | | | | $ 9,700,000 | | | | |
Revolving Credit Commitments at Present [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Line of credit facility, certain financial terms | | | | The revolver expires on the earliest of (i) November 2, 2022; (ii) 91 days prior to the final maturity of any term loan under the credit facility if $200.0 million or more remains under such term loan on that date; or (iii) six months prior to the scheduled maturity of any affiliated subordinated indebtedness that is then outstanding. | | | | |
Revolving Credit Commitments at Present [Member] | Maximum [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Rate of commitment fees on the unused portion of revolving credit commitments | | | 0.50% | | | | | |
Revolving Credit Commitments at Present [Member] | Maximum [Member] | LIBOR [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | | 2.75% | | | | | |
Revolving Credit Commitments at Present [Member] | Maximum [Member] | Prime Rate [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | | 1.75% | | | | | |
Revolving Credit Commitments at Present [Member] | Minimum [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Rate of commitment fees on the unused portion of revolving credit commitments | | | 0.25% | | | | | |
Revolving Credit Commitments at Present [Member] | Minimum [Member] | LIBOR [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | | 1.75% | | | | | |
Revolving Credit Commitments at Present [Member] | Minimum [Member] | Prime Rate [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | | 0.75% | | | | | |
Term Loan A-1 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Original principal amount | | $ 250,000,000 | $ 250,000,000 | | | | | |
Quarterly principal payments of original principal amount | | $ 3,100,000 | | | | | | |
Rate of quarterly principal payments of original principal amount | | 1.25% | | | | | | |
Final payment at maturity representing the original principal amount | | $ 187,500,000 | 187,500,000 | | | | | |
Rate of Final payment at maturity representing the original principal amount | | 75.00% | | | | | | |
Financing costs | | $ 1,800,000 | 1,800,000 | | | | | |
Net proceeds from debt | | $ 248,200,000 | | | | | | |
Term Loan A-1 [Member] | Maximum [Member] | LIBOR [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | 2.75% | | | | | | |
Term Loan A-1 [Member] | Maximum [Member] | Prime Rate [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | 1.75% | | | | | | |
Term Loan A-1 [Member] | Minimum [Member] | LIBOR [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | 1.75% | | | | | | |
Term Loan A-1 [Member] | Minimum [Member] | Prime Rate [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | 0.75% | | | | | | |
Term Loan M [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Original principal amount | | $ 800,000,000 | 800,000,000 | | | | | |
Quarterly principal payments of original principal amount | | $ 2,000,000 | | | | | | |
Rate of quarterly principal payments of original principal amount | | 0.25% | | | | | | |
Final payment at maturity representing the original principal amount | | $ 742,000,000 | 742,000,000 | | | | | |
Rate of Final payment at maturity representing the original principal amount | | 92.75% | | | | | | |
Financing costs | | $ 9,200,000 | 9,200,000 | | | | | |
Net proceeds from debt | | $ 790,800,000 | | | | | | |
Debt instrument prepayment fee percentage | | 1.00% | | | | | | |
Term Loan M [Member] | LIBOR [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | 2.00% | | | | | | |
Term Loan M [Member] | Prime Rate [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | 1.00% | | | | | | |
Term Loan M [Member] | Minimum [Member] | LIBOR [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | 0.75% | | | | | | |
Term Loan M [Member] | Minimum [Member] | Prime Rate [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Floating rate margin | | 1.75% | | | | | | |
Bank Credit Facility [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Revolving credit commitment outstanding | | | | $ 1,420,000,000 | | | | |
Bank Credit Facility [Member] | Maximum [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Leverage ratio | | | | 500.00% | | | | |
Bank Credit Facility [Member] | Minimum [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Interest coverage ratio | | | | 200.00% | | | | |
Bank Credit Facility [Member] | Revolving Credit Commitments at Present [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Revolving credit commitments | | $ 375,000,000 | $ 375,000,000 | $ 375,000,000 | | | | |
Expiration date of revolving credit commitments | | | | Nov. 2, 2022 | | | | |
Bank Credit Facility [Member] | Term Loan A-1 [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Revolving credit commitment outstanding | | | | | 246,900,000 | | | |
Expiration date of revolving credit commitments | | | | Nov. 2, 2022 | | | | |
Bank Credit Facility [Member] | Term Loan M [Member] | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | |
Revolving credit commitment outstanding | | | | | $ 798,000,000 | | | |
Expiration date of revolving credit commitments | | | | Jan. 15, 2025 | | | | |