Summary of Basis Used to Measure Defined Benefit Plans Assets at Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	$ 98,242	$ 101,916
U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	23,465	26,787
U.S. Small / Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	10,184	7,950
International, Equity
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	11,986	14,797
U.S. Intermediate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	15,000	14,906
U.S. Short Duration
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	8,935	8,817
U.S. High Yield
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	7,758	5,270
International, Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	15,249	20,776
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	1,829	2,329
Other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	3,836	284
Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	78,660	81,013
Level 1 | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	23,465	26,787
Level 1 | U.S. Small / Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	7,482	7,950
Level 1 | International, Equity
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	7,786	8,275
Level 1 | U.S. Intermediate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	15,000	14,906
Level 1 | U.S. Short Duration
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	8,935	8,817
Level 1 | U.S. High Yield
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	6,922	5,270
Level 1 | International, Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	7,241	6,679
Level 1 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	1,829	2,329
Level 1 | Other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	19,582	20,903
Level 2 | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 2 | U.S. Small / Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	2,702	0
Level 2 | International, Equity
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	4,200	6,522
Level 2 | U.S. Intermediate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 2 | U.S. Short Duration
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 2 | U.S. High Yield
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	836	0
Level 2 | International, Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	8,008	14,097
Level 2 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 2 | Other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	3,836	284
Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 3 | U.S. Large Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 3 | U.S. Small / Mid Cap
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 3 | International, Equity
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 3 | U.S. Intermediate
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 3 | U.S. Short Duration
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 3 | U.S. High Yield
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 3 | International, Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 3 | Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	0	0
Level 3 | Other
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets	$ 0	$ 0