Fair Value Measurements - Assets Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	$ 5,651	$ 6,736
Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	4,825	4,979
Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	826	1,292
Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents		465
Recurring [Member] \| Short Term Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	463
Recurring [Member] \| Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	4,825	4,979
Recurring [Member] \| Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	363	1,292
Recurring [Member] \| Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents		465
Recurring [Member] \| Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	12,407	12,413
Recurring [Member] \| Quoted Prices in Active Markets (Level 1) [Member] \| Short Term Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents
Recurring [Member] \| Quoted Prices in Active Markets (Level 1) [Member] \| Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents
Recurring [Member] \| Quoted Prices in Active Markets (Level 1) [Member] \| Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents
Recurring [Member] \| Quoted Prices in Active Markets (Level 1) [Member] \| Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents		465
Recurring [Member] \| Quoted Prices in Active Markets (Level 1) [Member] \| Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	12,407	12,413
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Short Term Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	463
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	363	1,292
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents
Recurring [Member] \| Significant Other Observable Inputs (Level 2) [Member] \| Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Short Term Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Failed Auction Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents	4,825	4,979
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Brokered Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Certificates of Deposit [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents
Recurring [Member] \| Significant Unobservable Inputs (Level 3) [Member] \| Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Cash Equivalents