Fair Value Measurements - Reconciliation of Beginning and Ending Balances of Contingent Consideration Liability Categorized Under Level 3 of Fair Value (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total (gains) losses for period: Included in net income	$ (62,000)	$ 1,565,000	$ 0
Contingent Consideration [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Opening balance	685,000	0
Transfers into level 3	0	0
Transfers out of level 3	0	0
Total (gains) losses for period: Included in net income	62,000	(1,565,000)
Total gains or losses for period Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Settlements	0	0
Issuances	0	2,250,000
Closing balance	$ 747,000	$ 685,000