Changes in Accumulated Other Comprehensive Income (Loss) By Component (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance			$ 553,902	$ 443,145
Ending balance	$ 789,820	$ 537,978	789,820	537,978
Unrealized Gains (Losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	4,895	(1,825)	(4,602)	1,156
Other comprehensive income (loss) before reclassifications	15	598	9,529	(2,426)
Amounts reclassified from accumulated other comprehensive income (loss) to net income	1	10	(16)	53
Net current-period other comprehensive income (loss)	16	608	9,513	(2,373)
Ending balance	4,911	(1,217)	4,911	(1,217)
Foreign Currency Items
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(768)	(136)	(584)	(14)
Other comprehensive income (loss) before reclassifications	190	(435)	6	(557)
Amounts reclassified from accumulated other comprehensive income (loss) to net income	0	0	0	0
Net current-period other comprehensive income (loss)	190	(435)	6	(557)
Ending balance	(578)	(571)	(578)	(571)
Total Unrealized Gains (Losses)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	4,127	(1,961)	(5,186)	1,142
Other comprehensive income (loss) before reclassifications	205	163	9,535	(2,983)
Amounts reclassified from accumulated other comprehensive income (loss) to net income	1	10	(16)	53
Net current-period other comprehensive income (loss)	206	173	9,519	(2,930)
Ending balance	4,333	(1,788)	4,333	(1,788)
Unrealized Gain (Loss) on Cash Flow Hedge
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(4,554)	(2,153)	(2,798)	(1,264)
Other comprehensive income (loss) before reclassifications	556	(1,464)	(1,577)	(2,353)
Amounts reclassified from accumulated other comprehensive income (loss) to net income	439	0	816	0
Net current-period other comprehensive income (loss)	995	(1,464)	(761)	(2,353)
Ending balance	(3,559)	(3,617)	(3,559)	(3,617)
Total
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(427)	(4,114)	(7,984)	(122)
Other comprehensive income (loss) before reclassifications	761	(1,301)	7,958	(5,336)
Amounts reclassified from accumulated other comprehensive income (loss) to net income	440	10	800	53
Net current-period other comprehensive income (loss)	1,201	(1,291)	8,758	(5,283)
Ending balance	$ 774	$ (5,405)	$ 774	$ (5,405)