Fair Value Measurements and Disclosures - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Mortgage-backed securities $ 28,750 $ 33,742
Investment in mutual fund 34,932 47,979
Derivative assets 105 493
Derivative liability 425 352
US Treasury Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in mutual fund 1,501  
Municipal Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in mutual fund 4,681 4,270
Mutual Fund [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in mutual fund   9,967
Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in mutual fund 1,501  
Level 1 [Member] | US Treasury Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in mutual fund 1,501  
Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Mortgage-backed securities 28,750 33,742
Investment in mutual fund 33,431 47,979
Derivative assets 105 493
Derivative liability 425 352
Level 2 [Member] | Municipal Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in mutual fund 4,681 4,270
Level 2 [Member] | Mutual Fund [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investment in mutual fund   $ 9,967