Equity Awards - Summary of Option Award Activity (Detail)	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Total Stock Options Outstanding:
Total Stock Options Outstanding, Beginning balance (in shares) | shares	211,487
Total Stock Options Outstanding, Forfeited, Canceled (in shares) | shares	(51,411)
Total Stock Options Outstanding, Ending balance (in shares) | shares	160,076
Weighted Average Exercise Price per Share:
Weighted Average Exercise Price per Share, Beginning balance (in dollars per share) | $ / shares	$ 36.94
Weighted Average Exercise Price per Share, Forfeited, Canceled (in dollars per share) | $ / shares	40.12
Weighted Average Exercise Price per Share, Ending balance (in dollars per share) | $ / shares	$ 35.92
Nonvested Stock Options:
Nonvested Stock Options, Beginning balance (in shares) | shares	0
Nonvested Stock Options, Forfeited, Canceled (in shares) | shares	0
Nonvested Stock Options, Ending balance (in shares) | shares	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted Average Grant Date Fair Value per Share, Beginning balance (in dollars per share) | $ / shares	$ 0.00
Weighted Average Grant Date Fair Value per Share, Forfeited, Canceled (in dollars per share) | $ / shares	0.00
Weighted Average Grant Date Fair Value per Share, Ending balance (in dollars per share) | $ / shares	$ 0.00