Employee Benefit Plans - Summary of Pension Plan Assets (Detail) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		$ 51,940	$ 50,959
Total Pension Plan Assets, excluding investments measured at net asset value		45,707	44,502
Investments measured at net asset value	[1]	6,233	6,457
Investments in equity securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		21,365	18,236
Investments in equity securities | Us Large Cap Equity Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	4,031	3,641
Investments in equity securities | Us Mid Cap Equity Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	1,677	1,577
Investments in equity securities | United States Equity Small Cap
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	845	865
Investments in equity securities | International All Cap Equity
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[3]	9,574	9,416
Investments in equity securities | Alternative Strategies
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[4]	5,238	2,737
Debt securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		19,594	21,086
Debt securities | Fixed Income
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[5]	16,958	18,565
Debt securities | High Yield Asset Backed Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[5]	2,636	2,521
Other
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		4,748	5,180
Other | Commodities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[6]	2,134	1,365
Other | Real Estate
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[7]	2,116	2,529
Other | Guaranteed deposit
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[8]	498	1,286
Quoted Prices in Active Markets (Level 1)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		45,209	43,216
Quoted Prices in Active Markets (Level 1) | Investments in equity securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		21,365	18,236
Quoted Prices in Active Markets (Level 1) | Investments in equity securities | Us Large Cap Equity Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	4,031	3,641
Quoted Prices in Active Markets (Level 1) | Investments in equity securities | Us Mid Cap Equity Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	1,677	1,577
Quoted Prices in Active Markets (Level 1) | Investments in equity securities | United States Equity Small Cap
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	845	865
Quoted Prices in Active Markets (Level 1) | Investments in equity securities | International All Cap Equity
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[3]	9,574	9,416
Quoted Prices in Active Markets (Level 1) | Investments in equity securities | Alternative Strategies
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[4]	5,238	2,737
Quoted Prices in Active Markets (Level 1) | Debt securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		19,594	21,086
Quoted Prices in Active Markets (Level 1) | Debt securities | Fixed Income
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[5]	16,958	18,565
Quoted Prices in Active Markets (Level 1) | Debt securities | High Yield Asset Backed Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[5]	2,636	2,521
Quoted Prices in Active Markets (Level 1) | Other
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		4,250	3,894
Quoted Prices in Active Markets (Level 1) | Other | Commodities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[6]	2,134	1,365
Quoted Prices in Active Markets (Level 1) | Other | Real Estate
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[7]	2,116	2,529
Quoted Prices in Active Markets (Level 1) | Other | Guaranteed deposit
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[8]	0	0
Significant Other Observable Inputs (Level 2)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		0	0
Significant Other Observable Inputs (Level 2) | Investments in equity securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		0	0
Significant Other Observable Inputs (Level 2) | Investments in equity securities | Us Large Cap Equity Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	0	0
Significant Other Observable Inputs (Level 2) | Investments in equity securities | Us Mid Cap Equity Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	0	0
Significant Other Observable Inputs (Level 2) | Investments in equity securities | United States Equity Small Cap
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	0	0
Significant Other Observable Inputs (Level 2) | Investments in equity securities | International All Cap Equity
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[3]	0	0
Significant Other Observable Inputs (Level 2) | Investments in equity securities | Alternative Strategies
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[4]	0	0
Significant Other Observable Inputs (Level 2) | Debt securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		0	0
Significant Other Observable Inputs (Level 2) | Debt securities | Fixed Income
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[5]	0	0
Significant Other Observable Inputs (Level 2) | Debt securities | High Yield Asset Backed Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[5]	0	0
Significant Other Observable Inputs (Level 2) | Other
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		0	0
Significant Other Observable Inputs (Level 2) | Other | Commodities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[6]	0	0
Significant Other Observable Inputs (Level 2) | Other | Real Estate
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[7]	0	0
Significant Other Observable Inputs (Level 2) | Other | Guaranteed deposit
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[8]	0	0
Significant Unobservable Inputs (Level 3)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		498	1,286	$ 1,144
Significant Unobservable Inputs (Level 3) | Investments in equity securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		0	0
Significant Unobservable Inputs (Level 3) | Investments in equity securities | Us Large Cap Equity Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	0	0
Significant Unobservable Inputs (Level 3) | Investments in equity securities | Us Mid Cap Equity Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	0	0
Significant Unobservable Inputs (Level 3) | Investments in equity securities | United States Equity Small Cap
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[2]	0	0
Significant Unobservable Inputs (Level 3) | Investments in equity securities | International All Cap Equity
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[3]	0	0
Significant Unobservable Inputs (Level 3) | Investments in equity securities | Alternative Strategies
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[4]	0	0
Significant Unobservable Inputs (Level 3) | Debt securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		0	0
Significant Unobservable Inputs (Level 3) | Debt securities | Fixed Income
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[5]	0	0
Significant Unobservable Inputs (Level 3) | Debt securities | High Yield Asset Backed Securities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[5]	0	0
Significant Unobservable Inputs (Level 3) | Other
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets		498	1,286
Significant Unobservable Inputs (Level 3) | Other | Commodities
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[6]	0	0
Significant Unobservable Inputs (Level 3) | Other | Real Estate
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[7]	0	0
Significant Unobservable Inputs (Level 3) | Other | Guaranteed deposit
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total Pension Plan Assets	[8]	$ 498	$ 1,286

[1] Certain investments that were measured at net asset value per share have not been classified in the fair value hierarchy. These amounts are presented to reconcile to total pension plan assets.

[2] Includes funds that invest primarily in United States common stocks.

[3] Includes funds that invest primarily in foreign equities and emerging markets equities.

[4] Includes funds that actively invest in both equity and debt securities, funds that sell short securities and funds that provide long-term capital appreciation. The funds may invest in debt securities below investment grade.

[5] Includes funds that invest in investment grade and fixed income securities.

[6] Includes funds that invest primarily in commodity-linked derivative instruments and fixed income securities.

[7] Includes funds that invest primarily in real estate.

[8] Includes investment in a group annuity product issued by an insurance company.