Fair Value Measurements - Fair Value of Company's Fixed Rate Senior Notes and Junior Subordinated Debentures (Detail) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
Jun. 30, 2014 |
---|---|---|---|
6.375% Senior Notes | |||
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] | |||
Interest rate on Senior Notes | 6.375% | 6.375% | 6.375% |
6.375% Senior Notes | Carrying Amount | |||
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] | |||
Debt | $ 323,888 | $ 322,777 | |
6.375% Senior Notes | Estimated Fair Value | |||
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] | |||
Debt | 304,013 | 271,425 | |
Junior Subordinated Debentures | Carrying Amount | |||
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] | |||
Debt | 128,640 | 129,707 | |
Junior Subordinated Debentures | Estimated Fair Value | |||
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items] | |||
Debt | $ 139,831 | $ 131,691 |